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|
<html>
<head>
<meta http-equiv="Content-Language" content="en-us">
<meta name="GENERATOR" content="Microsoft FrontPage 5.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<title>
$if $TARGET; == BOOST
Filesystem V3 Reference
$def WHAT "reference documentation"
$def SNIPPET_FILE "boost_snippets.html"
$def HEADER "boost/filesystem.hpp"
$def NAMESPACE boost
$def SUBNAMESPACE filesystem
$def NAMESPACE_BEGIN "namespace boost
{
namespace filesystem
{"
$def NAMESPACE_END " } // namespace filesystem
} // namespace boost"
$else
Filesystem TR2 Proposal
$def WHAT "Clause"
$def SNIPPET_FILE "tr2_snippets.html"
$def HEADER "files"
$def NAMESPACE std
$def SUBNAMESPACE files
$def NAMESPACE_BEGIN "namespace std { namespace tr2 { namespace files {
"
$def NAMESPACE_END "} } } // namespaces std::tr2::files"
$endif
</title>
<style type="text/css">
$include "../../../../../doc/src/minimal.css"
</style>
</head>
<body>
$snippet frontmatter "$SNIPPET_FILE;"
<h2><a name="TOC">Table of Contents</a></h2>
<table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%">
<tr>
<td width="33%" valign="top"><a href="#Introduction">Introduction</a><br>
<a href="#Definitions">Definitions</a><br>
<a href="#Conformance">Conformance</a><br>
<a href="#Header-filesystem-synopsis">
Header <code><$HEADER;></code> synopsis</a><br>
<a href="#Error-reporting">Error reporting</a><br>
<a href="#class-path">Class <code>path</code></a><br>
<a href="#path-Conversions"><code>path</code> conversions</a><br>
<a href="#path-Conversions-to-native-format"><code>path</code>
conversions to native format</a><br>
<a href="#path-Conversions-to-generic-format"><code>path</code>
conversions to generic format</a><br>
<a href="#path-Encoding-conversions"><code>path</code>
encoding conversions</a><br>
<a href="#path-Requirements"><code>path</code> requirements</a><br>
<a href="#path-constructors"><code>path</code> constructors</a><br>
<a href="#path-assignments"><code>path</code> assignments</a><br>
<a href="#path-appends"><code>path</code> appends</a><br>
<a href="#path-modifiers"><code>path</code> modifiers</a><br>
<a href="#path-native-format-observers"><code>path</code> native
format observers</a><br>
<a href="#path-generic-format-observers"><code>path</code> generic
format observers</a><br>
<a href="#path-decomposition"><code>path</code> decomposition</a><br>
<a href="#path-query"><code>path</code> query</a><br>
<a href="#path-iterators"><code>path</code> iterators</a><br>
<a href="#path-deprecated-functions"><code>path</code> deprecated functions</a><br>
<a href="#path-non-member-functions"><code>path</code> non-member functions</a><br>
<a href="#path-inserter-extractor"><code>path</code> inserters and extractors</a><br>
<a href="#Class-filesystem_error">Class <code>filesystem_error</code></a><br>
<a href="#filesystem_error-members"><code>filesystem_error</code>
constructors</a><br>
<code>f</code><a href="#filesystem_error-path1"><code>ilesystem_error</code> path1</a><br>
<a href="#filesystem_error-path2"><code>filesystem_error</code> path2</a><br>
<a href="#filesystem_error-what"><code>filesystem_error</code><code>
</code>what</a></td>
<td width="33%" valign="top">
<a href="#Enum-file_type">Enum <code>file_type</code></a><br>
<a href="#Enum-perms">Enum <code>perms</code></a><br>
<a href="#file_status">Class
<code>file_status</code></a><br>
<a href="#file_status">
<code>file_status</code></a><a href="#file_status-constructors"> constructors</a><br>
<code><a href="#file_status-modifiers">file_status-modifiers</a></code><a href="#directory_entry-observers"> observers</a><br>
<code><a href="#file_status-observers">file_status-observers</a></code><a href="#directory_entry-modifiers"> modifiers</a><br>
<a href="#Class-directory_entry">Class <code>directory_entry</code></a><br>
<a href="#directory_entry-constructors"><code>directory_entry</code> constructors</a><br>
<a href="#directory_entry-observers"><code>directory_entry</code> observers</a><br>
<a href="#directory_entry-modifiers"><code>directory_entry</code> modifiers</a><br>
<a href="#Class-directory_iterator">Class <code>directory_iterator</code></a><br>
<a href="#directory_iterator-members"><code>directory_iterator</code>
members</a><br>
<a href="#Class-recursive_directory_iterator">Class <code>recursive_directory_iterator</code></a><br>
<a href="#Operational-functions">
Operational functions</a><br>
<code>   <a href="#absolute">absolute</a><br>
<a href="#canonical">canonical</a><br>
<a href="#copy">copy</a><br>
<a href="#copy_directory">copy_directory</a><br>
<a href="#copy_file">copy_file</a><br>
<a href="#copy_symlink">copy_symlink</a><br>
  <a href="#create_directories">create_directories</a><br>
  <a href="#create_directory">create_directory</a><br>
  <a href="#create_hard_link">create_hard_link</a><br>
  <a href="#create_symlink">create_symlink</a><br>
  <a href="#current_path">current_path</a><br>
  <a href="#exists">exists</a><br>
  <a href="#equivalent">equivalent</a><br>
  <a href="#file_size">file_size</a><br>
<a href="#hard_link_count">hard_link_count</a><br>
<a href="#initial_path">initial_path</a><br>
  i<a href="#is_directory">s_directory</a><br>
  <a href="#is_empty">is_empty</a></code></td>
<td width="34%" valign="top">
<code>   <a href="#is_other">is_other</a><br>
  <a href="#is_regular_file">is_regular_file</a><br>
  <a href="#is_symlink">is_symlink</a><br>
  <a href="#last_write_time">last_write_time</a><br>
<a href="#permissions">permissions</a><br>
<a href="#read_symlink">read_symlink</a><br>
  <a href="#remove">remove</a><br>
  <a href="#remove_all">remove_all</a><br>
  <a href="#rename">rename</a><br>
<a href="#resize_file">resize_file</a><br>
  <a href="#space">space</a><br>
  <a href="#status">status</a><br>
  <a href="#status_known">status_known</a><br>
  <a href="#symlink_status">symlink_status</a><br>
  <a href="#system_complete">system_complete</a><br>
  <a href="#temp_directory_path">temp_directory_path</a><br>
</code> <code> <a href="#unique_path">unique_path</a></code><br>
<a href="#File-streams">File streams</a><br>
<a href="#Path-decomposition-table">Path decomposition table</a><br>
<a href="#long-path-warning">Warning: Long paths on Windows and the
extended-length <b>\\?\ </b>prefix</a><br>
<a href="#Acknowledgements">Acknowledgements</a><br>
<a href="#References">References</a><br>
</td>
</tr>
</table>
$snippet wording_prefix "$SNIPPET_FILE;"
<p>This $WHAT; describes components that perform operations on file systems and
their components, such as paths, regular files, and directories.</p>
<p>Operating systems such as <i>MAC OS, UNIX</i>, and <i>Windows</i> are
mentioned in this $WHAT; for purposes of illustration or to give guidance to
implementers. No slight to other operating systems is implied or intended.</p>
<p><a name="Footnote-3">Footnote 3</a>: <i>MAC OS</i>® is a registered trademark
of Apple Inc.</p>
<p><a name="Footnote-4">Footnote 4</a>: <i>Windows</i>® is a registered
trademark of Microsoft Corporation.</p>
<h2><a name="Conformance">Conformance</a></h2>
<p>Behavior is sometimes specified by reference to ISO/IEC 9945:2003, <i>
<a href="http://www.unix.org/single_unix_specification/">POSIX</a></i>. How such behavior is actually implemented is unspecified.</p>
<blockquote>
<p>[<i>Note:</i> This constitutes an "as if" rule for implementation of
operating system dependent behavior. Presumably implementations will usually call native
operating system API's. <i>--end note</i>]</p>
</blockquote>
<p>Implementations are encouraged, but not required, to support such behavior
as it is defined by <i>POSIX</i>. Implementations shall document any
behavior that differs from the <i>POSIX</i> defined behavior. Implementations that do not support exact <i>POSIX</i> behavior are
encouraged to provide behavior as close to <i>POSIX</i> behavior as is reasonable given the
limitations of actual operating systems and file systems. If an implementation cannot provide any
reasonable behavior, the implementation shall report an error in an
implementation-defined manner.</p>
<blockquote>
<p>[<i>Note:</i> Such errors might be reported by an #error directive, a <code>
static_assert</code>, a <code>filesystem_error</code> exception, a special
return value, or some other manner. <i>--end note</i>]</p>
</blockquote>
<p>Implementations are not required to provide behavior that is not supported by
a particular file system.</p>
<blockquote>
<p>[<i>Example:</i> The <a href="http://en.wikipedia.org/wiki/FAT_filesystem">
FAT file system</a> used by some memory cards, camera memory, and floppy discs
does not support hard links, symlinks, and many other features of more capable
file systems. Implementations are only required to support the FAT features
supported by the host operating system. <i>-- end example</i>]</p>
</blockquote>
<p>Specific operating systems such as <i>OpenVMS</i>,
<i>UNIX</i>, and <i>Windows</i> are mentioned only for purposes of illustration or to
give guidance to users and implementers. No slight to other operating systems is implied
or intended. When unlikely to cause confusion, the term <i>POSIX</i> is
sometimes used to refer to "POSIX-compliant operating systems".</p>
<p>The behavior of functions described in this
reference
may differ from their specification in
the presence of <a href="#Race-condition">file system races</a>. No diagnostic is required.</p>
<p>If the possibility of a file system race would make it unreliable for a program to
test for a precondition before calling a function described in this $WHAT;, <i>
Requires</i> is not specified for the condition. Instead, the condition is
specified as a <i>Throws</i> condition.</p>
<blockquote>
<p>[<i>Note:</i> As a design practice, preconditions are not specified when it
is unreasonable for a program to detect them prior to calling the function. <i>
-- end note</i>]</p>
</blockquote>
<h2><a name="Definitions">Definitions</a></h2>
<p>The following definitions shall apply throughout this reference documentation:</p>
<p><i><b><a name="File">File</a>:</b> </i>An object that can be written to, or read from, or both. A file
has certain attributes, including type. File types include regular files
and directories. Other types of files, such as symbolic links, may be supported by the
implementation.</p>
<p><b><i><a name="File-system">File system</a>:</i></b> A collection of files and certain of their attributes.</p>
<p><b><i><a name="Filename">Filename</a>:</i></b> The name of a file. Slash and
0x00
characters are not permitted. Implementations may define additional
characters or specific names that are not permitted. Filenames <code>.</code>
and <code>..</code> have special meaning. Implementations may define
additional filenames that have special meaning.</p>
<blockquote>
<p><i>[Note:</i> Most operating systems prohibit the ASCII control characters
(0x00-0x1F) in filenames.</p>
<p>Windows prohibits the characters 0x00-0x1F, <code>"</code>,<code>
*</code>,<code> :</code>,<code> <</code>,<code> ></code>,<code> ?</code>,<code>
\</code>,<code> /</code>, and<code> |</code> <i>--end note]</i></p>
</blockquote>
<p><b><i><a name="Path">Path</a>:</i></b> A sequence of elements that identify
the location of a file within a filesystem. The elements are the <i>root-name<sub>opt</sub></i>, <i>
root-directory<sub>opt</sub></i>, and an optional sequence of filenames. [<i>Note:</i>
A <a href="#Pathname">pathname</a> is the concrete representation of a path. <i>--end note</i>]</p>
<p><b><i><a name="Absolute-path">Absolute path</a>:</i></b> A path that
unambiguously
identifies the location of a file within a file system without reference to an
additional starting location. The format is implementation defined. </p>
<blockquote>
<p><i>[Note:</i> For POSIX-like implementations, including<b> </b>Unix
variants, Linux, and Mac OS X, only paths
that begin with a slash are absolute paths.</p>
<p>For Windows-like implementations, including <a href="http://www.cygwin.com/">
Cygwin</a> and
<a href="http://www.mingw.org/">MinGW</a>, only paths that begin with a drive
specifier followed by a slash, or begin with two slashes, are absolute paths. <i>--end
note]</i></p>
</blockquote>
<p><i><b><a name="Relative-path">Relative path</a>:</b></i> A path that only
unambiguously
identifies the location of a file within a filesystem when resolved relative to
a starting location. The format is implementation defined. [<i>Note:</i>
Paths "." and ".." are considered to be relative paths. <i>--end note</i>]</p>
<p><i><b><a name="Canonical-path">Canonical path</a>:</b></i> An absolute path that has
no elements which are symbolic links, and no dot or dot dot elements.</p>
<p><i><b><a name="Pathname">Pathname</a>:</b> </i>A character string that represents a
path. Pathnames are formatted according to the generic pathname format or an implementation defined
native pathname format.</p>
<p><b><i><a name="generic-pathname-format">Generic pathname format:</a></i></b></p>
<blockquote>
<p><i>pathname:<br>
root-name<sub>opt</sub>
root-directory<sub>opt</sub> relative-path<sub>opt</sub></i></p>
<p><i>root-name:<br>
implementation-defined</i></p>
<blockquote>
<blockquote>
<p>[<i>Note:</i> Most POSIX and Windows based operating systems define a name
beginning with two slashes (or backslashes, for Windows) as a root-name
identifying network locations. Windows defines a single letter followed by a
<code>":"</code> as a root-name identifying a disc drive. <i>--end note</i>]</p>
</blockquote>
</blockquote>
<p><i>root-directory:<br>
directory-separator</i></p>
<p><i>relative-path:<br>
filename<br>
relative-path
directory-separator<br>
relative-path
directory-separator filename</i></p>
<p><i>filename:<br>
name<br>
</i><code>"."</code><i><br>
</i><code>
".."</code></p>
<p><i>directory-separator:<br>
<code>"/"<br>
"/"</code> directory-separator</i></p>
<p>Multiple successive <i>directory-separator</i> characters are considered to
be the same as one <i>directory-separator</i> character. The <i>filename</i>
<code>"."</code> is considered to be a reference to the current directory. The
<i>filename</i> <code>".."</code> is considered to be a reference to the current
directory. Specific <i>filenames</i> may have special meaning for a particular
operating system.</p>
</blockquote>
<p><b><i><a name="native-pathname-format">Native pathname format:</a></i></b>
An implementation defined format. [<i>Note:</i> For POSIX-like operating
systems, the native format is the same as the generic format. For Windows, the
native format is similar to the generic format, but the directory-separator
characters can be either slashes or backslashes. <i>--end note</i>]</p>
<p><i><b><a name="Link">Link</a>:</b> </i>A directory entry object that associates a
filename with a file. On some file systems, several directory entries can
associate names with the same file.</p>
<p><b><i><a name="Hard-link">Hard link</a>:</i></b> A link to an existing file. Some
file systems support multiple hard links to a file. If the last hard link to a
file is removed, the file itself is removed.</p>
<blockquote>
<p>[<i>Note:</i> A hard link can be thought of as a shared-ownership smart
pointer to a file.<i> -- end note</i>]<i> </i></p>
</blockquote>
<p><i><a name="Symbolic-link">S<b>ymbolic link</b></a><b>:</b> </i>A type of file with the
property that when the file is encountered during pathname resolution, a string
stored by the file is used to modify the pathname resolution.</p>
<blockquote>
<p>[<i>Note:</i> A symbolic link can be thought of as a raw pointer to a file.
If the file pointed to does not exist, the symbolic link is said to be a
"dangling" symbolic link.<i> -- end note</i>]<i> </i></p>
</blockquote>
<p><b><i><a name="Race-condition">File system race</a>:</i></b> The condition that occurs
when multiple threads, processes, or computers interleave access and
modification of
the same object within a file system.</p>
<p><b><i><a name="Dot">Dot</a>, Dot Dot:</i></b> Synonyms for the filenames <code>"."</code>
and <code>".."</code>, respectively. The dot filename names the current
directory. The dot dot filename names the parent directory.</p>
<h2><a name="Header-filesystem-synopsis">Header <code><$HEADER;></code> synopsis</a></h2>
<pre>$NAMESPACE_BEGIN;
class <a href="#class-path">path</a>;
void swap(path& lhs, path& rhs);
bool lexicographical_compare(path::iterator first1, path::iterator last1,
path::iterator first2, path::iterator last2);
std::size_t <a href="#hash_value">hash_value</a>(const path& p);
bool operator==(const path& lhs, const path& rhs);
bool operator!=(const path& lhs, const path& rhs);
bool operator< (const path& lhs, const path& rhs);
bool operator<=(const path& lhs, const path& rhs);
bool operator> (const path& lhs, const path& rhs);
bool operator>=(const path& lhs, const path& rhs);
path operator/ (const path& lhs, const path& rhs);
std::ostream& operator<<( std::ostream& os, const path& p );
std::wostream& operator<<( std::wostream& os, const path& p );
std::istream& operator>>( std::istream& is, path& p );
std::wistream& operator>>( std::wistream& is, path& p )
class <a href="#Class-filesystem_error">filesystem_error</a>;
class <a href="#Class-directory_entry">directory_entry</a>;
class <a href="#Class-directory_iterator">directory_iterator</a>;
class <a href="#Class-recursive_directory_iterator">recursive_directory_iterator</a>;
enum <a name="file_type" href="#Enum-file_type">file_type</a>
{
status_error, file_not_found, regular_file, directory_file,
symlink_file, block_file, character_file, fifo_file, socket_file,
type_unknown
};
enum <a href="#Enum-perms">perms</a>
{
no_perms,
owner_read, owner_write, owner_exe, owner_all,
group_read, group_write, group_exe, group_all,
others_read, others_write, others_exe, others_all, all_all,
set_uid_on_exe, set_gid_on_exe, sticky_bit,
perms_mask, perms_not_known,
add_perms, remove_perms, symlink_perms
};
class <a href="#file_status">file_status</a>;
struct <a name="space_info">space_info</a> // returned by <a href="#space" style="text-decoration: none">space</a> function
{
uintmax_t capacity;
uintmax_t free;
uintmax_t available; // free space available to a non-privileged process
};
enum class <a name="copy_option">copy_option</a>
{
none
fail_if_exists = none,
overwrite_if_exists
};
enum class <a name="symlink_option">symlink_option</a>
{
none
no_recurse = none,
recurse
};
// <a href="#Operational-functions">operational functions</a>
path <a href="#absolute">absolute</a>(const path& p, const path& base=current_path());
path <a href="#canonical">canonical</a>(const path& p, const path& base = current_path());
path <a href="#canonical">canonical</a>(const path& p, system::error_code& ec);
path <a href="#canonical">canonical</a>(const path& p, const path& base, system::error_code& ec);
void <a href="#copy">copy</a>(const path& from, const path& to);
void <a href="#copy">copy</a>(const path& from, const path& to, system::error_code& ec);
void <a href="#create_directory">copy_directory</a>(const path& from, const path& to);
void <a href="#create_directory">copy_directory</a>(const path& from, const path& to, system::error_code& ec);
void <a href="#copy_file">copy_file</a>(const path& from, const path& to);
void <a href="#copy_file">copy_file</a>(const path& from, const path& to, system::error_code& ec);
void <a href="#copy_file">copy_file</a>(const path& from, const path& to, <a href="#copy_option">copy_option</a> option);
void <a href="#copy_file">copy_file</a>(const path& from, const path& to, <a href="#copy_option">copy_option</a> option,
system::error_code& ec);
void <a href="#copy_symlink">copy_symlink</a>(const path& existing_symlink, const path& new_symlink);
void <a href="#copy_symlink">copy_symlink</a>(const path& existing_symlink, const path& new_symlink, system::error_code& ec);
bool <a href="#create_directories">create_directories</a>(const path& p);
bool <a href="#create_directories">create_directories</a>(const path& p, system::error_code& ec);
bool <a href="#create_directory">create_directory</a>(const path& p);
bool <a href="#create_directory">create_directory</a>(const path& p, system::error_code& ec);
void <a href="#create_directory_symlink">create_directory_symlink</a>(const path& to, const path& new_symlink);
void <a href="#create_directory_symlink">create_directory_symlink</a>(const path& to, const path& new_symlink, system::error_code& ec);
void <a href="#create_hard_link">create_hard_link</a>(const path& to, const path& new_hard_link);
void <a href="#create_hard_link">create_hard_link</a>(const path& to, const path& new_hard_link, system::error_code& ec);
void <a href="#create_symlink">create_symlink</a>(const path& to, const path& new_symlink);
void <a href="#create_symlink">create_symlink</a>(const path& to, const path& new_symlink, system::error_code& ec);
path <a href="#current_path">current_path</a>();
path <a href="#current_path">current_path</a>(system::error_code& ec);
void <a href="#current_path">current_path</a>(const path& p);
void <a href="#current_path">current_path</a>(const path& p, system::error_code& ec);
bool <a href="#exists">exists</a>(file_status s) noexcept;
bool <a href="#exists">exists</a>(const path& p);
bool <a href="#exists">exists</a>(const path& p, system::error_code& ec) noexcept;
bool <a href="#equivalent">equivalent</a>(const path& p1, const path& p2);
bool <a href="#equivalent">equivalent</a>(const path& p1, const path& p2, system::error_code& ec);
uintmax_t <a href="#file_size">file_size</a>(const path& p);
uintmax_t <a href="#file_size">file_size</a>(const path& p, system::error_code& ec);
uintmax_t <a href="#hard_link_count">hard_link_count</a>(const path& p);
uintmax_t <a href="#hard_link_count">hard_link_count</a>(const path& p, system::error_code& ec);
const path& <a href="#initial_path">initial_path</a>();
const path& <a href="#initial_path">initial_path</a>(<code>system::error_code& ec</code>);
bool <a href="#is_directory">is_directory</a>(file_status s) noexcept;
bool <a href="#is_directory2">is_directory</a>(const path& p);
bool <a href="#is_directory2">is_directory</a>(const path& p, system::error_code& ec) noexcept;
bool <a href="#is_empty">is_empty</a>(const path& p);
bool <a href="#is_empty">is_empty</a>(const path& p, system::error_code& ec);
bool <a href="#is_other">is_other</a>(file_status s) noexcept;
bool <a href="#is_other2">is_other</a>(const path& p,);
bool <a href="#is_other2">is_other</a>(const path& p, system::error_code& ec) noexcept;
bool <a href="#is_regular_file">is_regular_file</a>(file_status s) noexcept;
bool i<a href="#is_regular_file2">s_regular_file</a>(const path& p);
bool i<a href="#is_regular_file2">s_regular_file</a>(const path& p, system::error_code& ec) noexcept;
bool <a href="#is_symlink">is_symlink</a>(file_status s noexcept);
bool <a href="#is_symlink2">is_symlink</a>(const path& p);
bool <a href="#is_symlink2">is_symlink</a>(const path& p, system::error_code& ec) noexcept;
std::time_t <a href="#last_write_time">last_write_time</a>(const path& p);
std::time_t <a href="#last_write_time">last_write_time</a>(const path& p, system::error_code& ec);
void <a href="#last_write_time2">last_write_time</a>(const path& p, const std::time_t new_time);
void <a href="#last_write_time2">last_write_time</a>(const path& p, const std::time_t new_time, system::error_code& ec);
path <a href="#read_symlink">read_symlink</a>(const path& p);
path <a href="#read_symlink">read_symlink</a>(const path& p, system::error_code& ec);
bool <a href="#remove">remove</a>(const path& p);
bool <a href="#remove">remove</a>(const path& p, system::error_code& ec);
uintmax_t <a href="#remove_all">remove_all</a>(const path& p);
uintmax_t <a href="#remove_all">remove_all</a>(const path& p, system::error_code& ec);
void <a href="#rename">rename</a>(const path& from, const path& to);
void <a href="#rename">rename</a>(const path& from, const path& to, system::error_code& ec);
void <a href="#resize_file">resize_file</a>(const path& p, uintmax_t size);
void <a href="#resize_file2">resize_file</a>(const path& p, uintmax_t size, system::error_code& ec);
<a href="#space_info">space_info</a> <a href="#space">space</a>(const path& p);
<a href="#space_info">space_info</a> <a href="#space">space</a>(const path& p, system::error_code& ec);
<a href="#file_status">file_status</a> <a href="#status">status</a>(const path& p);
<a href="#file_status">file_status</a> <a href="#status">status</a>(const path& p, system::error_code& ec) noexcept;
bool <a href="#status_known">status_known</a>(file_status s) noexcept;
<a href="#file_status">file_status</a> <a href="#symlink_status">symlink_status</a>(const path& p);
<a href="#file_status">file_status</a> <a href="#symlink_status">symlink_status</a>(const path& p, system::error_code& ec) noexcept;
path <a href="#system_complete">system_complete</a>(const path& p);
path <a href="#system_complete">system_complete</a>(const path& p, system::error_code& ec);
path <a href="#temp_directory_path">temp_directory_path</a>();
path <a href="#temp_directory_path">temp_directory_path</a>(system::error_code& ec);
path <a href="#unique_path">unique_path</a>(const path& model="%%%%-%%%%-%%%%-%%%%");
path <a href="#unique_path">unique_path</a>(const path& model, system::error_code& ec);
$NAMESPACE_END;</pre>
<h2><a name="Error-reporting">Error reporting</a></h2>
<p>Filesystem library functions often provide two overloads, one that
throws an exception to report file system errors, and another that sets an
<code>error_code</code>.</p>
<blockquote>
<p>[<i>Note:</i> This supports two common use cases:</p>
<ul>
<li>Uses where file system
errors are truly exceptional and indicate a serious failure. Throwing an
exception is the most appropriate response. This is the preferred default for
most everyday programming.<br>
</li>
<li>Uses where file system system errors are routine and do not necessarily represent
failure. Returning an error code is the most appropriate response. This allows
application specific error handling, including simply ignoring the error.</li>
</ul>
<p><i>--end note</i>]</p>
</blockquote>
<p>Functions <b>not</b> having an argument of type
<code>system::error_code&</code>
report errors as follows, unless otherwise specified:</p>
<ul>
<li>When a call by the
implementation to an operating system or other underlying API results in an
error that prevents the function from meeting its specifications, an exception
of type
<code>filesystem_error</code> is thrown.<br>
</li>
<li>Failure to allocate storage is reported by throwing an exception as described in the C++ standard,
17.6.4.10 [res.on.exception.handling].<br>
</li>
<li>Destructors throw nothing.</li>
</ul>
<p>Functions having an argument of type
<code>system::error_code&</code> report errors as follows, unless otherwise
specified:</p>
<ul>
<li>If a call by the
implementation to an operating system or other underlying API results in an
error that prevents the function from meeting its specifications, the
<code>system::error_code&</code> argument is set as
appropriate appropriate for the specific error. Otherwise, <code>clear()</code>
is called on the
<code>system::error_code&</code> argument.<br>
</li>
<li>Failure to allocate storage is reported by
throwing an exception as described in the C++ standard,
17.6.4.10 [res.on.exception.handling].</li>
</ul>
<h2><a name="class-path">Class <code>path</code></a></h2>
<p>An object of class <code>path</code> represents a <a href="#Path">path</a>,
and contains a <a href="#Pathname">pathname</a> Such an object is concerned only with the lexical and syntactic aspects
of a path. The path does not necessarily exist in external storage, and the
pathname is not necessarily valid for the current operating
system or for a particular file system.</p>
<blockquote>
<p>[<i>Example:</i> A <a href="#long-path-warning">long path name on Windows</a>
is an example of an innocuous appearing path that is not actually valid. <i>--
end example</i>]</p>
</blockquote>
<pre>$NAMESPACE_BEGIN;
class path
{
public:
typedef <b><i><a href="#value_type">see below</a></i></b> value_type; // char for POSIX, wchar_t for Windows
typedef std::basic_string<value_type> string_type;
typedef std::codecvt<wchar_t, char, std::mbstate_t> codecvt_type;
// <a href="#path-constructors">constructors</a> and destructor
path();
path(const path& p);
path(path&& p) noexcept;
template <class <a href="#Source">Source</a>>
path(Source const& source, const codecvt_type& cvt=codecvt());
template <class <a href="#InputIterator">InputIterator</a>>
path(InputIterator begin, InputIterator end, const codecvt_type& cvt=codecvt());
~path();
// <a href="#path-assignments">assignments</a>
path& operator=(const path& p);
path& operator=(path&& p) noexcept;
template <class <a href="#Source">Source</a>>
path& operator=(Source const& source);
template <class <a href="#Source">Source</a>>
path& assign(Source const& source, const codecvt_type& cvt)
template <class <a href="#InputIterator">InputIterator</a>>
path& assign(InputIterator begin, InputIterator end, const codecvt_type& cvt=codecvt());
// <a href="#path-appends">appends</a>
path& operator/=(const path& p);
template <class <a href="#Source">Source</a>>
path& operator/=(Source const& source);
template <class <a href="#Source">Source</a>>
path& append(Source const& source, const codecvt_type& cvt);
template <class <a href="#InputIterator">InputIterator</a>>
path& append(InputIterator begin, InputIterator end, const codecvt_type& cvt=codecvt());
// <a href="#path-modifiers">modifiers</a>
void <a href="#path-clear">clear</a>();
path& <a href="#absolute">make_absolute</a>(const path& base);
path& <a href="#path-make_preferred">make_preferred</a>(); // POSIX: no effect. Windows: convert slashes to backslashes
path& <a href="#path-remove_filename">remove_filename</a>();
path& <a href="#path-replace_extension">replace_extension</a>(const path& new_extension = path());
void <a href="#path-swap">swap</a>(path& rhs);
// <a href="#path-native-format-observers">native format observers</a>
const string_type& <a href="#native">native</a>() const noexcept; // native format, encoding
const value_type* <a href="#c_str">c_str</a>() const noexcept; // native().c_str()
template <class String>
String <a href="#string-template">string</a>(const codecvt_type& cvt=codecvt()) const; // native format
const string <a href="#string">string</a>(const codecvt_type& cvt=codecvt()) const; // native format
const wstring <a href="#wstring">wstring</a>(const codecvt_type& cvt=codecvt()) const; // ditto
const u16string <a href="#u16string">u16string</a>() const; // ditto
const u32string <a href="#u32wstring">u32string</a>() const; // ditto
// <a href="#path-generic-format-observers">generic format observers</a>
template <class String>
String <a href="#generic_string-template">generic_string</a>() const;
const string <a href="#generic_string">generic_string</a>(const codecvt_type& cvt=codecvt()) const; // generic format
const wstring <a href="#generic_wstring">generic_wstring</a>(const codecvt_type& cvt=codecvt()) const; // ditto
const u16string <a href="#generic_u16string">generic_u16string</a>() const; // ditto
const u32string <a href="#generic_u32wstring">generic_u32string</a>() const; // ditto
// <a href="#path-decomposition">decomposition</a>
path <a href="#path-root_name">root_name</a>() const;
path <a href="#path-root_directory">root_directory</a>() const;
path <a href="#path-root_path">root_path</a>() const;
path <a href="#path-relative_path">relative_path</a>() const;
path <a href="#path-parent_path">parent_path</a>() const;
path <a href="#path-filename">filename</a>() const;
path <a href="#path-stem">stem</a>() const;
path <a href="#path-extension">extension</a>() const;
// <a href="#path-query">query</a>
bool <a href="#path-query">empty</a>() const;
bool <a href="#path-has_root_name">has_root_name</a>() const;
bool <a href="#path-has_root_directory">has_root_directory</a>() const;
bool <a href="#path-has_root_path">has_root_path</a>() const;
bool <a href="#path-has_relative_path">has_relative_path</a>() const;
bool <a href="#path-has_parent_path">has_parent_path</a>() const;
bool <a href="#path-has_filename">has_filename</a>() const;
bool <a href="#path-has_stem">has_stem</a>() const;
bool <a href="#path-has_extension">has_extension</a>() const;
bool <a href="#path-is_absolute">is_absolute</a>() const;
bool <a href="#path-is_relative">is_relative</a>() const;
// <a href="#path-iterators">iterators</a>
class iterator;
typedef iterator const_iterator;
iterator begin() const;
iterator end() const;
// <a href="#path_encoding">encoding conversion</a>
static std::locale <a href="#path-imbue">imbue</a>( const std::locale& loc );
static const codecvt_type & <a href="#path-codecvt">codecvt</a>();
private:
string_type pathname; // <b><i>exposition only</i></b>
};
$NAMESPACE_END;</pre>
<p><code><a name="value_type">value_type</a></code> is an implementation-defined
<code>typedef</code> for the
character type used by the operating system to represent pathnames.</p>
<p>Member functions described as returning <code>const string</code>, <code>
const wstring</code>, <code>const u16string</code>, or <code>const u32string</code> are permitted to return <code>const string&</code>, <code>const
wstring&</code>, <code>const u16string&</code>, or <code>const u32string&</code>,
respectively.</p>
<blockquote>
<p>[<i>Note:</i> This allows implementations to avoid unnecessary copies when no
conversion is required.
Return-by-value is specified as
<code>const</code> to ensure programs won't break if moved to a return-by-reference
implementation. <i>--
end note</i>]</p>
</blockquote>
<h3><a name="path-Conversions"><code>path</code> Conversions</a></h3>
<h4><a name="path-Conversions-to-native-format"><code>path</code> Conversions to
native format</a></h4>
<p>Member function arguments that take character sequences representing paths
may use the <a href="#generic-pathname-format">generic pathname format</a> or
the <a href="#native-pathname-format">native pathname format</a>. If such an
argument uses the generic format, an implementation defined conversion to native format is performed
during the processing of the argument. </p>
<blockquote>
<p>[<i>Note:</i> No conversion occurs on POSIX and Windows since they have
native formats that conform to the generic format. <i>--end note</i>]</p>
<p>[<i>Rationale:</i> There is no unambiguous way for an implementation to
always be able distinguish between native format and generic format arguments.
This is by design as it simplifies use. Should an implementation encounter an
operating system where disambiguation is required, an implementation defined
native format prefix can be introduced to identify the native format. <i>-- end
rationale</i>]</p>
</blockquote>
<table align="center" border="1" cellpadding="3" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" bgcolor="#D7EEFF" width="90%">
<tr>
<td>
Class <code>path</code> does not currently map invalid characters in
filenames to valid characters. In the future we might add something like
this:<blockquote>
<p>When converting filenames to the native operating system format,
implementations are encouraged, but not required, to convert otherwise invalid
characters or character sequences to valid characters or character sequences.
Such conversions are implementation-defined.</p>
<blockquote>
<p>[<i>Note:</i> Filename conversion allows much wider portability of both
programs and filenames that would otherwise be possible.</p>
<p>Implementations are encouraged to base conversion on existing standards or
practice. Examples include the Uniform Resource Locator escape syntax of a percent sign (<code>'%'</code>)
followed by two hex digits representing the character value. On
<i>OpenVMS</i>, which does not allow percent signs in filenames, a dollar sign (<code>'$'</code>)
followed by two hex digits is the existing practice, as is converting lowercase
letters to uppercase.<i> -- end note.</i>]</p>
</blockquote>
</blockquote>
</td>
</tr>
</table>
<p>If the native format requires
paths for regular files to be formatted differently from paths for directories, the
path shall be treated as a directory path if last element is a separator,
otherwise it shall be treated as a regular file path.</p>
<blockquote>
<p>[<i>Note</i>: The above paragraph does not apply to POSIX and Windows since
they use the same format
for both regular file and directory pathnames. <i>--end note</i>]</p>
<p>[<i>Example:</i>
On <a href="http://en.wikipedia.org/wiki/OpenVMS">OpenVMS</a>, a path
constructed from <code>"/cats/jane"</code> would considered a regular file
path, and have a native format of <code>"[CATS]JANE"</code>, while a
path constructed from <code>"/cats/jane/"</code> would be considered a
directory path, and have a native format of <code>"[CATS.JANE]"</code>.
<i>--end example</i>]</p>
</blockquote>
<h4><a name="path-Conversions-to-generic-format"><code>path</code> Conversions
to generic format</a></h4>
<p><a href="#path-generic-format-observers">Generic format observer</a>
functions return strings formatted according to the
<a href="#generic-pathname-format">generic pathname format</a>. The conversion
from generic to native formats is implementation defined.</p>
<blockquote>
<p>[<i>Note:</i> For POSIX, no conversion is performed. For Windows, backslashes are converted to
forward slashes. <i>-- end note</i>]</p>
</blockquote>
<h4><a name="path-Encoding-conversions"><code>path</code> Encoding conversions</a></h4>
<p>If the value type of member function arguments that are character sequences
representing paths is not <code>value_type</code>,
and no <code>cvt</code> argument is supplied, conversion to <code>value_type</code>
occurs using an imbued locale. This imbued locale is initialized with a <code>
codecvt</code> facet appropriate for the operating system.</p>
<blockquote>
<p>For Apple OS X implementations, <code>path::value_type</code>
is <code>char</code>. The default imbued locale provides a UTF-8 <code>codecvt</code>
facet. [<i>Rationale:</i> "All BSD system functions expect their string
parameters to be in UTF-8 encoding and nothing else." See
<a href="http://developer.apple.com/mac/library/documentation/MacOSX/Conceptual/BPInternational/Articles/FileEncodings.html">
Apple docs</a>. <i>-- end rationale</i>]</p>
<p>For Windows-like implementations, including
<a href="http://www.mingw.org/">MinGW</a>, <code>path::value_type</code> is <code>
wchar_t</code>. The default imbued locale provides a <code>codecvt</code> facet
that invokes Windows <code>MultiByteToWideChar</code> or <code>
WideCharToMultiByte</code> API with a codepage of <code>CP_THREAD_ACP</code>
if Windows <code>AreFileApisANSI()</code>is true, otherwise codepage <code>
CP_OEMCP</code>. [<i>Rationale:</i> this is the current behavior of C and C++
programs that perform file operations using narrow character string to identify
paths. Changing this in the Filesystem library would be too surprising,
particularly where user input is involved. <i>-- end rationale</i>]</p>
<p>For all other implementations, including<b> </b>Linux, <code>path::value_type</code>
is <code>char</code>. The default imbued locale is <code>std::locale("")</code>.
[<i>Rationale:</i> ISO C specifies this as "the locale-specific native
environment", while POSIX says it "Specifies an implementation-defined native
environment." <i>-- end rationale</i>]</p>
</blockquote>
<h3><a name="path-Requirements"><code>path</code> Requirements</a></h3>
<p>Template parameters named <code><a name="InputIterator">InputIterator</a></code>
are required meet the
requirements for a C++ standard library <code>RandomIterator</code>
compliant iterator. The iterator's value type is required to be <code>char</code>, <code>
wchar_t</code>, <code>char16_t</code>, or <code>char32_t</code>.</p>
<p>Template parameters named <code><a name="Source">Source</a></code> are required to be one of:</p>
<ul>
<li>A container with a value type of <code>char</code>, <code>
wchar_t</code>, <code>char16_t</code>, or <code>char32_t</code>.</li>
<li>An iterator for a null terminated byte-string. The value type is required
to be <code>char</code>, <code>wchar_t</code>, <code>char16_t</code>, or <code>
char32_t</code>.</li>
<li>A C-array. The value type is required to be <code>char</code>, <code>
wchar_t</code>, <code>char16_t</code>, or <code>char32_t</code>.</li>
<li>A <code>boost::filesystem::directory_entry</code>.</li>
</ul>
<h3> <a name="path-constructors"> <code>
<font size="4">path</font></code> constructors</a></h3>
<pre><span style="background-color: #D7EEFF">path();</span></pre>
<blockquote>
<p><i>Postcondition:</i> <code>empty()</code>.</p>
</blockquote>
<pre>template <class <a href="#Source">Source</a>>
path(Source const& source, const codecvt_type& cvt=codecvt());</pre>
<pre>template <class <a href="#InputIterator">InputIterator</a>>
path(InputIterator begin, InputIterator end, const codecvt_type& cvt=codecvt());</pre>
<blockquote>
<p><i>Effects:</i> Stores the contents [<code>begin</code>,<code>end</code>)
or <code>source</code> in <code>pathname</code>. If the contents are in the
generic format and the generic format is unacceptable to the operating
system's API, they are converted to the native format. [<i>Note:</i> For
POSIX and Windows implementations, the generic format is already
acceptable as a native format, so no generic to native conversion is
performed. <i>--end note</i>]</p>
<p>
<i>Remarks:</i> If the value type of [<code>begin</code>,<code>end</code>)
or <code>source</code> is not <code>value_type</code>, conversion is performed
by <code>cvt</code>.</p>
</blockquote>
<h3> <a name="path-assignments"> <code>
<font size="4">path</font></code> assignments</a></h3>
<pre>template <class <a href="#Source">Source</a>>
path& operator=(Source const& source);</pre>
<pre>template <class <a href="#Source">Source</a>>
path& assign(Source const& source, const codecvt_type& cvt);</pre>
<pre>template <class <a href="#InputIterator">InputIterator</a>>
path& assign(InputIterator begin, InputIterator end, const codecvt_type& cvt=codecvt());</pre>
<blockquote>
<p><i>Effects:</i> Stores the contents [<code>begin</code>,<code>end</code>)
or <code>source</code> in <code>pathname</code>. If the contents are in the
generic format, they are converted to the native format. [<i>Note:</i> For
POSIX and Windows based implementations, the generic format is already
acceptable as a native format, so no generic to native conversion is
performed. <i>--end note</i>]</p>
<p>
<i>Returns: </i><code>*this</code></p>
<p>
<i>Remarks:</i> If the value type of [<code>begin</code>,<code>end</code>)
or <code>source</code> is not <code>value_type</code>, conversion is performed
by <code>cvt</code>.</p>
</blockquote>
<h3> <a name="path-appends"><code><font size="4"> path</font></code> appends</a></h3>
<p>The append operations use <code>operator/=</code> to denote their semantic
effect of appending the platform's preferred directory separator when needed. The
preferred
directory separator is implementation-defined.</p>
<blockquote>
<p align="left">[<i>Note: </i>For POSIX-like implementations, including<b> </b>
Unix variants, Linux, and Mac OS X, the preferred directory separator is a
single forward slash.</p>
<p align="left">For Windows-like implementations, including
<a href="http://www.cygwin.com/">Cygwin</a> and
<a href="http://www.mingw.org/">MinGW</a>, the preferred directory
separator is a single backslash.<i>--end note</i>]</p>
</blockquote>
<pre>path& operator/=(const path& p);</pre>
<blockquote>
<p><i>Effects:</i></p>
<blockquote>
Appends the preferred directory separator to the contained pathname, unless:<ul>
<li>an added separator
would be redundant, or</li>
<li>would change an relative path to an absolute path, or</li>
<li><code>p.empty()</code>, or</li>
<li><code>*p.native().cbegin()</code> is a directory separator.</li>
</ul>
<p>Appends <code>p.native()</code> to <code>pathname</code>.</p>
</blockquote>
<p><i>Returns: </i><code>*this</code></p>
</blockquote>
<pre>template <class <a href="#Source">Source</a>>
path& operator/=(Source const & source);</pre>
<pre>template <class <a href="#Source">Source</a>>
path& append(Source const & source, const codecvt_type& cvt);</pre>
<pre>template <class <a href="#InputIterator">InputIterator</a>>
path& append(InputIterator begin, InputIterator end, const codecvt_type& cvt=codecvt());</pre>
<blockquote>
<p><i>Effects:</i></p>
<blockquote>
<p>Appends a native directory separator to the contained pathname, unless:</p>
<ul>
<li>an added separator
would be redundant, or</li>
<li>would change an relative path to an absoute path, or</li>
<li><code>p.empty()</code>, or</li>
<li><code>*p.native().cbegin()</code> is a separator.</li>
</ul>
<p>Appends the contents [<code>begin</code>,<code>end</code>)
or <code>source</code> to <code>pathname</code>. If the contents are in the
generic format, they are converted to the native format. [<i>Note:</i> For
POSIX and Windows based implementations, the generic format is already
acceptable as a native format, so no generic to native conversion is
performed. <i>--end note</i>]</p>
</blockquote>
<p><i>Remarks:</i> If the value type of [<code>begin</code>,<code>end</code>)
or <code>source</code> is not <code>value_type</code>, conversion is performed
by <code>cvt</code>.</p>
<p><i>Returns: </i><code>*this</code></p>
</blockquote>
<h3> <a name="path-modifiers"> <code>
<font size="4">path</font></code> modifiers</a></h3>
<pre>void <a name="path-clear">clear</a>();</pre>
<blockquote>
<p><i>Postcondition:</i> <code>this->empty()</code> is true.</p>
</blockquote>
<pre>path& <a name="path-make_preferred">make_preferred</a>();</pre>
<blockquote>
<p><i>Effects:</i> The contained pathname is converted to the preferred native
format. [<i>Note:</i> On Windows, the effect is to replace slashes with
backslashes. On POSIX, there is no effect. <i>-- end note</i>]</p>
<p><i>Returns:</i> <code>*this</code></p>
</blockquote>
<pre>path& <a name="path-remove_filename">remove_filename</a>();</pre>
<blockquote>
<p><i>Returns: </i>As if, <code>*this = parent_path();</code></p>
<p>[<i>Note:</i> This function is needed to efficiently implement <code>
directory_iterator</code>. It is exposed to allow additional uses. The actual
implementation may be much more efficient than <code>*this = parent_path()</code> <i>-- end
note</i>]</p>
</blockquote>
<pre>path& <a name="path-replace_extension">replace_extension</a>(const path& new_extension = path());</pre>
<blockquote>
<p><i>Postcondition: </i> <code>extension() == <i>replacement</i></code>,
where <code><i>replacement</i></code> is <code>new_extension</code> if <code>
new_extension.empty() || new_extension[0] ==</code> the dot character,
otherwise <code><i>replacement</i></code> is the dot character followed by
<code>new_extension</code>.</p>
<p><i>Returns:</i> <code>*this</code></p>
</blockquote>
<pre><code>void <a name="path-swap">swap</a>(path& rhs) noexcept;</code></pre>
<blockquote>
<p><i>Effects:</i>
Swaps the contents of the two paths.</p>
<p><i>Complexity: </i>
constant time.</p>
</blockquote>
<h3> <a name="path-native-format-observers"><code><font size="4">path</font></code>
native format observers</a></h3>
<p>The string returned by all native format observers is in the
<a href="#native-pathname-format">native pathname format</a>.</p>
<pre>const string_type& <a name="native">native</a>() const noexcept;</pre>
<blockquote>
<p><i>Returns:</i> <code>pathname</code>.</p>
</blockquote>
<pre>const value_type* <a name="c_str">c_str</a>() const noexcept;</pre>
<blockquote>
<p><i>Returns:</i> <code>pathname.c_str()</code>.</p>
</blockquote>
<pre>template <class String>
String <a name="string-template">string</a>(const codecvt_type& cvt=codecvt()) const;</pre>
<blockquote>
<p><i>Returns:</i> <code>pathname</code>.</p>
<p><i>Remarks:</i> If <code>string_type</code> is a different type than <code>
String</code>, conversion is performed by <code>cvt</code>.</p>
</blockquote>
<pre>const string <a name="string">string</a>(const codecvt_type& cvt=codecvt()) const;
const wstring <a name="wstring">wstring</a>(const codecvt_type& cvt=codecvt()) const;
const u16string <a name="u16string">u16string</a>() const;
const u32wstring <a name="u32wstring">u32wstring</a>() const; </pre>
<blockquote>
<p><i>Returns:</i> <code>pathname</code>.</p>
<p><i>Remarks:</i> If <code>string_type</code> is a different type than
function's return type, conversion is performed by <code>cvt</code>.</p>
<p>If <code>string_type</code> is the same type as the
function's return type, the function is permitted to return by <code>const&</code>
rather than <code>const</code> value. [<i>Note:</i> For POSIX, this occurs for
<code>string()</code>, for Windows, <code>wstring()</code>. <i>--end note</i>]</p>
</blockquote>
<h3> <a name="path-generic-format-observers"><code><font size="4">path</font></code>
generic format observers</a></h3>
<p>The string returned by all generic format observers is in the
<a href="#generic-pathname-format">generic pathname format</a>.</p>
<p>[<i>Note:</i> For POSIX, no conversion occurs, since the native format and
generic format are the same. For Windows, backslashes are converted to slashes
<i>--end note</i>]</p>
<pre>template <class String>
String <a name="generic_string-template">generic_string</a>(const codecvt_type& cvt=codecvt()) const;</pre>
<blockquote>
<p><i>Returns:</i> <code>pathname</code>.</p>
<p><i>Remarks:</i> If <code>string_type</code> is a different type than <code>
String</code>, conversion is performed by
<code>cvt</code>.</p>
</blockquote>
<pre>const string <a name="generic_string">generic_string</a>(const codecvt_type& cvt=codecvt()) const;
const wstring <a name="generic_wstring">generic_wstring</a>(const codecvt_type& cvt=codecvt()) const;
const u16string <a name="generic_u16string">generic_u16string</a>() const;
const u32wstring <a name="generic_u32wstring">generic_u32wstring</a>() const; </pre>
<blockquote>
<p><i>Returns:</i> <code>pathname</code>.</p>
<p><i>Remarks:</i> If <code>string_type</code> is a different type than
function's return type, conversion is performed by <code>cvt</code>.</p>
<p>If <code>string_type</code> is of the same type as the
function's return type, and the generic format is the same as the native format,
the function is permitted to return by <code>const&</code> rather than <code>
const</code> value. [<i>Note:</i> For POSIX, this occurs for <code>string()</code>.
It never occurs for Windows, because backslashes must be converted to slashes.
<i>--end note</i>]</p>
</blockquote>
<h3> <a name="path-decomposition"> <code><font size="4">path</font></code>
decomposition</a></h3>
<p><span style="background-color: #E0E0E0"><i>See the
<a href="#Path-decomposition-table">Path decomposition table</a> for examples
for values returned by decomposition functions. The
<a href="tutorial.html#Using-path-decomposition">Tutorial</a> may also be
helpful.</i></span></p>
<pre>path <a name="path-root_name">root_name</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <i>root-name,</i> if <code>pathname</code> includes <i>
root-name</i>, otherwise <code>path()</code>. </p>
</blockquote>
<pre>path <a name="path-root_directory">root_directory</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <i>root-directory</i>, if <code>pathname</code> includes <i>
root-directory</i>, otherwise <code>path()</code>.</p>
<p>If <i>root-directory</i> is composed of <i>slash name</i>, <i>slash</i> is
excluded from the returned string.</p>
</blockquote>
<pre>path <a name="path-root_path">root_path</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>root_name() / root_directory()</code></p>
</blockquote>
<pre>path <a name="path-relative_path">relative_path</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> A <code>path</code> composed from <code>pathname</code>, if <code>
!empty()</code>, beginning
with the first <i>filename</i> after <i>root-path</i>. Otherwise, <code>path()</code>.</p>
</blockquote>
<pre>path <a name="path-parent_path">parent_path</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>(empty() || begin() == --end()) ? path() : <i>pp</i></code>, where
<code><i>pp</i></code> is constructed as if by
starting with an empty <code>path</code> and successively applying <code>
operator/=</code> for each element in the range <code>begin()</code>, <code>
--end()</code>.</p>
</blockquote>
<pre>path <a name="path-filename">filename</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>empty() ? path() : *--end()</code></p>
<p>[<i>Example:</i></p>
<blockquote>
<pre><code>std::cout << path("/foo/bar.txt").filename();</code> // outputs "<code>bar.txt</code>"</pre>
</blockquote>
<p> <i>--end example</i>]</p>
</blockquote>
<pre>path <a name="path-stem">stem</a>(const path& p) const;</pre>
<blockquote>
<p><i>Returns:</i> if <code>p.filename()</code>contains a dot but does not
consist solely of one or to two dots, returns
the substring of <code>p.filename()</code> starting at its beginning and
ending at the last dot (the dot is not included). Otherwise,
returns <code>
p.filename()</code>.</p>
<p>[<i>Example:</i></p>
<blockquote>
<pre><code>std::cout << path("/foo/bar.txt").stem();</code> // outputs "<code>bar</code>"
path p = "foo.bar.baz.tar";
for (; !p.extension().empty(); p = p.stem())
std::cout << p.extension() << '\n';
// outputs: .tar
// .baz
// .bar</pre>
</blockquote>
<p> <i>--end example</i>]</p>
</blockquote>
<pre>path <a name="path-extension">extension</a>(const path& p) const;</pre>
<blockquote>
<p><i>Returns:</i> if <code>p.filename()</code> contains a dot but does not
consist solely of one or to two dots, returns
the substring of <code>p.filename()</code> starting at the rightmost dot
and ending at the path's end. Otherwise, returns an empty <code>path</code>
object. </p>
<p><i>Remarks:</i> Implementations are permitted but not required to define additional
behavior for file systems which append additional elements to extensions, such
as alternate data streams or partitioned dataset names.</p>
<p>[<i>Example:</i></p>
<blockquote>
<pre><code>std::cout << path("/foo/bar.txt").extension(); //</code> outputs "<code>.txt</code>"</pre>
</blockquote>
<p> <i>--end example</i>]</p>
<p>[<i>Note:<b> </b></i>The dot is included in the return value so that
it is possible to distinguish between no extension and an empty extension. See
<a href="http://permalink.gmane.org/gmane.comp.lib.boost.devel/199744">
http://permalink.gmane.org/gmane.comp.lib.boost.devel/199744</a> for more
extensive rationale. <i>-- end note</i>]</p>
</blockquote>
<h3> <a name="path-query"> <code><font size="4">path</font></code> query</a></h3>
<pre>bool <a name="path-empty">empty</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>m_pathname.empty()</code>.</p>
</blockquote>
<pre>bool <a name="path-has_root_path">has_root_path</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!<a href="#path-root_path">root_path</a>().empty()</code></p>
</blockquote>
<pre>bool <a name="path-has_root_name">has_root_name</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!<a href="#path-root_name">root_name</a>().empty()</code></p>
</blockquote>
<pre>bool <a name="path-has_root_directory">has_root_directory</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!<a href="#path-root_directory">root_directory</a>().empty()</code></p>
</blockquote>
<pre>bool <a name="path-has_relative_path">has_relative_path</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!<a href="#path-has_relative_path">relative_path</a>().empty()</code></p>
</blockquote>
<pre>bool <a name="path-has_parent_path">has_parent_path</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!<a href="#path-parent_path">parent_path</a>().empty()</code></p>
</blockquote>
<pre>bool <a name="path-has_filename">has_filename</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!<a href="#path-filename">filename</a>().empty()</code></p>
</blockquote>
<pre>bool <a name="path-has_stem">has_stem</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!<a href="#path-stem">stem</a>().empty()</code></p>
</blockquote>
<pre>bool <a name="path-has_extension">has_extension</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!<a href="#path-has_extension">extension</a>().empty()</code></p>
</blockquote>
<pre>bool <a name="path-is_absolute">is_absolute</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>true</code>
if the elements of <code>root_path()</code> uniquely identify a directory, else <code>false</code>.</p>
<p>[<i>Note:</i> On POSIX,<code>
path("/foo").is_absolute()</code> returns <code>true</code>. On Windows, <code>
path("/foo").is_absolute()</code> returns <code>false</code>. <i>--end note</i>]</p>
</blockquote>
<pre>bool <a name="path-is_relative">is_relative</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!is_absolute()</code>.</p>
</blockquote>
<h3> <a name="path-iterators"> <code>
<font size="4">path</font></code> iterators</a></h3>
<p> A <code>path::iterator</code> is a constant iterator satisfying all
the requirements of a bidirectional iterator (C++ Std, 24.1.4 Bidirectional
iterators [lib.bidirectional.iterators]). Its <code>value_type</code> is <code>
path</code>.</p>
<p>Calling any non-const member function of a <code>path</code> object
invalidates all iterators referring to elements of that object.</p>
<p> The forward traversal order is as follows:</p>
<ul>
<li>The <i>root-name</i> element, if present.</li>
<li>The <i>root-directory</i> element, if present.</li>
<li>Each successive <i>filename</i> element, if present.</li>
<li><i>Dot</i>, if one or more trailing non-root <i>slash</i>
characters are present.</li>
</ul>
<p>The backward traversal order is the reverse of forward traversal.</p>
<pre>iterator begin() const;</pre>
<blockquote>
<p><i>Returns:</i> An iterator for the first present element in the traversal
list above. If no elements are present, the end iterator.</p>
</blockquote>
<pre>iterator end() const;</pre>
<blockquote>
<p><i>Returns:</i> The end iterator.</p>
</blockquote>
<h3><a name="path_encoding"><code><font size="4"> path</font></code> encoding</a> conversion</h3>
<pre>static std::locale <a name="path-imbue">imbue</a>(const std::locale& loc);</pre>
<blockquote>
<p><i>Effects:</i> Stores <code>loc</code> as the default locale for all
objects of type <code>path</code>.</p>
<p><i>Returns:</i> The previous default locale for all objects of type <code>
path</code>.</p>
</blockquote>
<pre>static const codecvt_type& <a name="path-codecvt">codecvt</a>();</pre>
<blockquote>
<p><i>Returns:</i> The <code>codecvt</code> facet for the default locale for
all objects of type <code>path</code>.</p>
</blockquote>
$if $TARGET; == BOOST
<h3> <a name="path-deprecated-functions"><code><font size="4"> path</font></code> deprecated functions</a></h3>
<p> Several member functions from previous versions of <code>class path</code>
have been deprecated, either because they have been renamed or because the
functionality is no longer desirable or has become obsolete.</p>
<p> Deprecated functions available by default; will be suppressed if <code>
BOOST_FILESYSTEM_NO_DEPRECATED</code> is defined:</p>
<blockquote>
<pre>path& remove_leaf() { return remove_filename(); }
path leaf() const { return filename(); }
path branch_path() const { return parent_path(); }
bool has_leaf() const { return !m_path.empty(); }
bool has_branch_path() const { return !parent_path().empty(); }</pre>
</blockquote>
<p> Deprecated functions not available by default; will be supplied if <code>
BOOST_FILESYSTEM_DEPRECATED</code> is defined:</p>
<blockquote>
<pre>const std::string file_string() const { return native_string(); }
const std::string directory_string() const { return native_string(); }
const std::string native_file_string() const { return native_string(); }
const std::string native_directory_string() const { return native_string(); }
const string_type external_file_string() const { return native(); }
const string_type external_directory_string() const { return native(); }</pre>
</blockquote>
$endif
<h3> <a name="path-non-member-functions"> <code><font size="4">path</font></code>
non-member functions</a></h3>
<pre>void swap( path& lhs, path& rhs )</pre>
<blockquote>
<p><i>Effects: </i><code>
lhs.swap(rhs)</code>.</p>
</blockquote>
<pre>bool lexicographical_compare(path::iterator first1, path::iterator last1,
path::iterator first2, path::iterator last2)</pre>
<blockquote>
<p><i>Returns:</i> <code>true</code> if the sequence of <code>native()</code>
strings for the elements defined by the range <code>[first1,last1)</code> is
lexicographically less than the sequence of <code>native()</code> strings for
the elements defined by the range <code>[first2,last2)</code>. Returns <code>
false</code> otherwise.</p>
<p><i>Remarks:</i> If two sequences have the same number of elements and their
corresponding elements are equivalent, then neither sequence is
lexicographically less than the other. If one sequence is a prefix of the
other, then the shorter sequence is lexicographically less than the longer
sequence. Otherwise, the lexicographical comparison of the sequences yields
the same result as the comparison of the first corresponding pair of elements
that are not equivalent.</p>
<pre> for ( ; first1 != last1 && first2 != last2 ; ++first1, ++first2) {
if (first1->native() < first2->native()) return true;
if (first2->native() < first1->native()) return false;
}
return first1 == last1 && first2 != last2;</pre>
<p>[<i>Note:</i> A <code>path</code> aware<code> lexicographical_compare</code>
is provided to avoid infinite recursion in <code>std::lexicographical_compare</code>
due to the <code>path</code> iterator's value type itself being <code>path</code>.
<i>--end note</i>]</p>
</blockquote>
<pre>std::size_t <a name="hash_value">hash_value</a> (const path& p);</pre>
<blockquote>
<p><i>Returns:</i> A hash value for the path <code>p</code>. If
for two paths, <code>p1 == p2</code> then
<code>hash_value(p1) == hash_value(p2)</code>.</p>
<p>This allows paths to be used with
<a href="../../../functional/hash/index.html">Boost.Hash</a>.</p>
</blockquote>
<pre>bool operator< (const path& lhs, const path& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>return lexicographical_compare(lhs.begin(), lhs.end(),
rhs.begin(), rhs.end())</code>.</p>
</blockquote>
<pre>bool operator<=(const path& lhs, const path& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>!(rhs < lhs)</code>.</p>
</blockquote>
<pre>bool operator> (const path& lhs, const path& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>rhs < lhs</code>.</p>
</blockquote>
<pre>bool operator>=(const path& lhs, const path& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>!(lhs < rhs)</code>.</p>
</blockquote>
<pre>bool operator==(const path& lhs, const path& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>!(lhs < rhs) && !(rhs < lhs)</code>.</p>
<p>[<i>Note:</i> Actual implementations may use an equivalent, but more
efficient, algorithm. <i>--end note</i>]</p>
<p>[<i>Note:</i> <a name="Path-equality">Path equality</a> and path
equivalence have different semantics.</p>
<p>Equality is determined by the <code>path</code>
non-member <code>operator==</code>, which considers the two path's lexical
representations only. Thus <code>path("foo") == "bar"</code> is never
<code>true</code>.</p>
<p>Equivalence is determined by the <a href="#equivalent"><code>equivalent()</code></a>
non-member function, which determines if two paths <a href="#Path">resolve</a> to the same file system entity.
Thus <code>equivalent("foo", "bar")</code> will be <code>true</code>
when both paths resolve to the same file.</p>
<p>Programmers wishing to determine if two paths are "the same" must decide if
"the same" means "the same representation" or "resolve to the same actual
file", and choose the appropriate function accordingly. <i>
-- end note</i>]</p>
</blockquote>
<pre>bool operator!=(const path& lhs, const path& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>!(lhs == rhs)</code>.</p>
</blockquote>
<pre>path operator/ (const path& lhs, const path& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>path(lhs) /= rhs</code>.</p>
</blockquote>
<h3> <a name="path-non-member-operators"><code><font size="4">path</font></code></a><a name="path-inserter-extractor"> inserter
and extractor</a></h3>
<p> The inserter and extractor delimit the string with double-quotes (<code>"</code>)
to ensure that paths with embedded spaces will round trip correctly. Ampersand (<code>&</code>)
is used as an escape character, so the path can itself contain double quotes.</p>
<pre>template <class Char, class Traits>
std::basic_ostream<Char, Traits>& operator<<(std::basic_ostream<Char, Traits>& os,
const path& p)
</pre>
<blockquote>
<p><i>Effects:</i>
<code>os << <a href="../../../io/doc/quoted_manip.html">
boost::io::quoted</a>(p.string<std::basic_string<Char>>(), static_cast<Char>('&'));</code></p>
<p><i>Returns:</i>
<code>os</code></p>
</blockquote>
<pre>template <class Char, class Traits>
inline std::basic_istream<Char, Traits>& operator>>(std::basic_istream<Char, Traits>& is,
path& p)
</pre>
<blockquote>
<p><i>Effects: </i>
<code> std::basic_string<Char> str;<br>
is >>
<a href="../../../io/doc/quoted_manip.html">boost::io::quoted</a>(str,
static_cast<Char>('&'));<br>
p = str;</code></p>
<p><i>Returns:</i>
<code>is</code></p>
</blockquote>
<h3><a name="Class-filesystem_error">Class <code>filesystem_error</code></a></h3>
<pre>$NAMESPACE_BEGIN;
class basic_filesystem_error : public system_error
{
public:
filesystem_error();
filesystem_error(const filesystem_error&);
<a href="#filesystem_error-2-arg">filesystem_error</a>(const std::string& what_arg,
system::error_code ec);
<a href="#filesystem_error-3-arg">filesystem_error</a>(const std::string& what_arg,
const path& p1, system::error_code ec);
<a href="#filesystem_error-4-arg">filesystem_error</a>(const std::string& what_arg,
const path& p1, const path& p2, system::error_code ec);
filesystem_error& filesystem_error(const filesystem_error&);
~filesystem_error();
filesystem_error& operator=(const filesystem_error&);
const path& <a href="#filesystem_error-path1">path1</a>() const;
const path& <a href="#filesystem_error-path2">path2</a>() const;
const char * <a href="#filesystem_error-what">what</a>() const;
};
$NAMESPACE_END;</pre>
<p>The class template <code>basic_filesystem_error</code> defines the type of
objects thrown as exceptions to report file system errors from functions described in this
$WHAT;.</p>
<h4> <a name="filesystem_error-members"> <code>filesystem_error</code> members</a></h4>
<pre><a name="filesystem_error-2-arg">filesystem_error</a>(const std::string& what_arg, error_code ec);</pre>
<blockquote>
<p><i>Postcondition:</i></p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="46%">
<tr>
<td width="18%"><b>Expression</b></td>
<td width="82%"><b>Value</b></td>
</tr>
<tr>
<td width="18%" bgcolor="#FFFFFF"><code>
runtime_error::what()</code></td>
<td width="82%" bgcolor="#FFFFFF">
<code><i>what_arg</i>.c_str()</code></td>
</tr>
<tr>
<td width="18%"><code>code()</code></td>
<td width="82%"><code>ec</code></td>
</tr>
<tr>
<td width="18%"><code>path1().empty()</code></td>
<td width="82%"><code>true</code></td>
</tr>
<tr>
<td width="18%"><code>path2().empty()</code></td>
<td width="82%"><code>true</code></td>
</tr>
</table>
</blockquote>
<pre><a name="filesystem_error-3-arg">filesystem_error</a>(const std::string& what_arg, const path_type& p1, error_code ec);</pre>
<blockquote>
<p><i>Postcondition:</i></p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="46%">
<tr>
<td width="18%"><b>Expression</b></td>
<td width="82%"><b>Value</b></td>
</tr>
<tr>
<td width="18%" valign="top"><code>
runtime_error::what()</code></td>
<td width="82%">
<code><i>what_arg</i>.c_str()</code></td>
</tr>
<tr>
<td width="18%" valign="top"><code>code()</code></td>
<td width="82%"><code>ec</code></td>
</tr>
<tr>
<td width="18%" valign="top"><code>path1()</code></td>
<td width="82%">Reference to stored copy of
<code>p1</code></td>
</tr>
<tr>
<td width="18%" valign="top"><code>path2().empty()</code></td>
<td width="82%"><code>true</code></td>
</tr>
</table>
</blockquote>
<pre><a name="filesystem_error-4-arg">filesystem_error</a>(const std::string& what_arg, const path_type& p1, const path_type& p2, error_code ec);</pre>
<blockquote>
<p><i>Postcondition:</i></p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="46%">
<tr>
<td width="18%"><b>Expression</b></td>
<td width="82%"><b>Value</b></td>
</tr>
<tr>
<td width="18%"><code>
runtime_error::what()</code></td>
<td width="82%">
<u>
<code><i>w</i></code></u><code><i>hat_arg</i>.c_str()</code></td>
</tr>
<tr>
<td width="18%"><code>code()</code></td>
<td width="82%"><code>ec</code></td>
</tr>
<tr>
<td width="18%"><code>path1()</code></td>
<td width="82%">Reference to stored copy of
<code>p1</code></td>
</tr>
<tr>
<td width="18%"><code>path2()</code></td>
<td width="82%">Reference to stored copy of
<code>p2</code></td>
</tr>
</table>
</blockquote>
<pre>const path& <a name="filesystem_error-path1">path1</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> Reference to copy of <code>p1</code> stored by the
constructor, or, if none, an empty path.</p>
</blockquote>
<pre>const path& <a name="filesystem_error-path2">path2</a>() const;</pre>
<blockquote>
<p><i>Returns:</i> Reference to copy of <code>p2</code> stored by the
constructor, or, if none, an empty path.</p>
</blockquote>
<pre>const char* <a name="filesystem_error-what">what</a>() const;</pre>
<blockquote>
<p><i>Returns: </i>A string containing <code>runtime_error::what()</code>. The exact format is unspecified.
Implementations are encouraged but not required to include <code>
path1.native_string()</code>if not empty, <code>path2.native_string()</code>if
not empty, and <code>system_error::what()</code> strings in the returned
string.</p>
</blockquote>
<h3><a name="Enum-file_type">Enum file_type</a></h3>
<p>This enum specifies constants uses to identify file types.</p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111">
<tr>
<td><b>Constant Name</b></td>
<td><b>Meaning</b></td>
</tr>
<tr>
<td><code>status_error</code></td>
<td>An error occurred while trying to obtain the status of the file. The
file simply not being found is <b><u>not</u></b> considered a status error.
</td>
</tr>
<tr>
<td><code>file_not_found</code></td>
<td>The file could not be found</td>
</tr>
<tr>
<td><code>regular_file</code></td>
<td>Regular file</td>
</tr>
<tr>
<td><code>directory_file</code></td>
<td>Directory file</td>
</tr>
<tr>
<td><code>symlink_file</code></td>
<td>Symbolic link file</td>
</tr>
<tr>
<td><code>block_file</code></td>
<td>Block special file</td>
</tr>
<tr>
<td><code>character_file</code></td>
<td>Character special file</td>
</tr>
<tr>
<td><code>fifo_file</code></td>
<td>FIFO or pipe file</td>
</tr>
<tr>
<td><code>socket_file</code></td>
<td>Socket file</td>
</tr>
<tr>
<td><code>type_unknown</code></td>
<td>The file exists, but it is of a system specific type not covered by any
of the above cases.</td>
</tr>
</table>
<h3><a name="Enum-perms">Enum perms</a></h3>
<p>This enum specifies bitmask constants uses to identify file
permissions. The POSIX standard specifies actual values, and those values have
been adopted here because they are very familiar and ingrained for many POSIX
users.</p>
<blockquote>
<p>Caution: Operating systems do not always support permissions as described in
the table.</p>
<p>There is much variation in the meaning of <code><a href="#sticky_bit">
sticky_bit</a></code>; do not use it unless you understand what it means for
your operating system.</p>
<p>There is much variation in how operating systems treat symlinks. See <code>
<a href="#symlink_perms">symlink_perms</a></code>.</p>
<p>Windows: All permissions except write are currently ignored. There is only a
single write permission; setting write permission for owner, group, or others
sets write permission for all, and removing write permission for owner, group,
or others removes write permission for all. </p>
</blockquote>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111">
<tr>
<td><b>Name</b></td>
<td align="center"><b>Value<br>
(octal)</b></td>
<td align="center"><b>POSIX<br>
macro</b></td>
<td><b>Definition or notes</b></td>
</tr>
<tr><td>
<p dir="ltr"><code>no_perms</code></td><td><code>0</code></td><td></td>
<td>There are no permissions set for the file. Note: <code>file_not_found</code> is
<code>no_perms</code> rather than <code>perms_not_known</code></td>
</tr>
<tr><td><code>owner_read</code></td><td><code>0400</code></td><td> <code>S_IRUSR</code></td>
<td> Read permission, owner</td>
</tr>
<tr><td><code>owner_write</code></td><td><code>0200</code></td><td> <code>S_IWUSR</code></td>
<td> Write permission, owner</td>
</tr>
<tr><td><code>owner_exe</code></td><td><code>0100</code></td><td> <code>S_IXUSR</code></td>
<td> Execute/search permission, owner</td>
</tr>
<tr><td><code>owner_all</code></td><td><code>0700</code></td><td> <code>S_IRWXU</code></td>
<td> Read, write, execute/search by owner; <code>owner_read | owner_write | owner_exe</code></td>
</tr>
<tr><td><code>group_read</code></td><td><code>040</code></td><td> <code>S_IRGRP</code></td>
<td> Read permission, group</td>
</tr>
<tr><td><code>group_write</code></td><td><code>020</code></td><td> <code>S_IWGRP</code></td>
<td> Write permission, group</td>
</tr>
<tr><td><code>group_exe</code></td><td><code>010</code></td><td> <code>S_IXGRP</code></td>
<td> Execute/search permission, group</td>
</tr>
<tr><td><code>group_all</code></td><td><code>070</code></td><td> <code>S_IRWXG</code></td>
<td> Read, write, execute/search by group; <code>group_read | group_write |
group_exe</code></td>
</tr>
<tr><td><code>others_read</code></td><td><code>04</code></td><td> <code>S_IROTH</code></td>
<td> Read permission, others</td>
</tr>
<tr><td><code>others_write</code></td><td><code>02</code></td><td> <code>S_IWOTH</code></td>
<td> Write permission, others</td>
</tr>
<tr><td><code>others_exe</code></td><td><code>01</code></td><td> <code>S_IXOTH</code></td>
<td> Execute/search permission, others</td>
</tr>
<tr><td><code>others_all</code></td><td><code>07</code></td><td> <code>S_IRWXO</code></td>
<td>Read, write, execute/search by others; <code>others_read | others_write | others_exe</code></td>
</tr>
<tr><td><code>all_all</code></td><td><code>0777</code></td><td> </td><td><code>owner_all | group_all | others_all</code></td>
</tr>
<tr><td><code>set_uid_on_exe</code></td><td><code>04000</code></td><td> <code>S_ISUID</code></td>
<td> Set-user-ID on execution</td>
</tr>
<tr><td><code>set_gid_on_exe</code></td><td><code>02000</code></td><td> <code>S_ISGID</code></td>
<td> Set-group-ID on execution</td>
</tr>
<tr><td><code><a name="sticky_bit">sticky_bit</a> </code> </td><td><code>01000</code></td><td> <code>S_ISVTX</code></td>
<td> Meaning varies; see <a href="http://en.wikipedia.org/wiki/Sticky_bit">http:en.wikipedia.org/wiki/Sticky_bit</a></td>
</tr>
<tr><td><code><a name="perms_mask">perms_mask</a></code></td><td><code>07777</code></td><td> </td>
<td><code>all_all | set_uid_on_exe | set_gid_on_exe | sticky_bit</code></td>
</tr>
<tr><td><code>perms_not_known</code></td><td><code>0xFFFF</code></td><td></td><td>
The permissions are not known, such as when a <code>file_status</code> object
is created without specifying the permissions</td>
</tr>
<tr><td>
<p dir="ltr"><code>add_perms</code></td><td><code>0x1000</code></td><td></td><td>
<p dir="ltr"><code>permissions()</code> adds the argument permission bits to the
file's current bits</td>
</tr>
<tr><td><code>remove_perms</code></td><td><code>0x2000</code></td><td></td><td>
<code>permissions()</code> removes the argument permission bits from the
file's current bits</td>
</tr>
<tr><td><code><a name="symlink_perms">symlink_perms</a></code></td><td><code>0x4000</code></td><td></td><td>
On POSIX <code>permissions()</code> resolves symlinks unless <code>symlink_perms</code>
is specified.
Meaningless on Windows as <code>permissions()</code> never resolves symlinks.
Meaningless on Mac OS X and some other BSD systems as <code>permissions()</code>
always resolves symlinks. Get over it.</td>
</tr>
</table>
<h3><a name="file_status">Class file_status</a></h3>
<pre>$NAMESPACE_BEGIN;
class file_status
{
public:
// <a href="#file_status-constructors">constructors</a>
file_status() noexcept;
explicit file_status(<a href="#file_type">file_type</a> ft, <a href="#Enum-perms">perms</a> prms = perms_not_known) noexcept;
// compiler generated
file_status(const file_status&) noexcept;
file_status& operator=(const file_status&) noexcept;
~file_status() noexcept;
// <a href="#file_status-observers">observers</a>
<a href="#file_type">file_type</a> type() const noexcept;
<a href="#Enum-perms">perms</a> permissions() const noexcept;
// <a href="#file_status-modifiers">modifiers</a>
void type(<a href="#file_type">file_type</a> ft) noexcept;
void permissions(<a href="#Enum-perms">perms</a> prms) noexcept;
};
$NAMESPACE_END;</pre>
<p>An object of type <code>file_status</code> stores information about the type
and permissions of a file.</p>
<h4 dir="ltr"><a name="file_status-constructors"><code>file_status</code>
constructors</a></h4>
<pre>explicit file_status() noexcept;</pre>
<blockquote>
<p><i>Postconditions:</i> <code>type() == status_error</code>, <code>
permissions() == perms_not_known</code>.</p>
</blockquote>
<pre>explicit file_status(<a href="#file_type">file_type</a> ft, <a href="#Enum-perms">perms</a> prms = perms_not_known) noexcept;</pre>
<blockquote>
<p><i>Postconditions:</i> <code>type() == ft</code>, <code>permissions() ==
prms</code>.</p>
</blockquote>
<h4 dir="ltr"><a name="file_status-observers"><code>file_status</code>
observers</a></h4>
<pre><a href="#file_type">file_type</a> type() const noexcept;</pre>
<blockquote>
<p><i>Returns: </i>The value of <code>type()</code> specified by the <i>
postconditions</i> of the most recent call to a constructor, operator=, or
<code>type(file_type)</code> function.</p>
</blockquote>
<pre><a href="#Enum-perms">perms</a> permissions() const noexcept;</pre>
<blockquote>
<p><i>Returns: </i>The value of <code>permissions()</code> specified by the <i>
postconditions</i> of the most recent call to a constructor, operator=, or
<code>permissions(perms)</code> function.</p>
</blockquote>
<h4 dir="ltr"><a name="file_status-modifiers"><code>file_status</code> modifiers</a></h4>
<pre>void type(<a href="#file_type">file_type</a> ft) noexcept;</pre>
<blockquote>
<p dir="ltr"><i>Postconditions:</i> <code>type() == ft</code>.</p>
</blockquote>
<pre>void permissions(<a href="#Enum-perms">perms</a> prms) noexcept;</pre>
<blockquote>
<p dir="ltr"><i>Postconditions:</i> <code>permissions() == prms</code>.</p>
</blockquote>
<h3><a name="Class-directory_entry">Class <code>directory_entry</code></a></h3>
<div dir="ltr">
<pre>$NAMESPACE_BEGIN;
class directory_entry
{
public:
// <a href="#directory_entry-constructors">constructors</a> and destructor
directory_entry();
directory_entry(const directory_entry&);
explicit directory_entry(const path_type& p, file_status st=file_status(),
file_status symlink_st=file_status());
~directory_entry();
// <a href="#directory_entry-modifiers">modifiers</a>
directory_entry& operator=(const directory_entry&);
void assign(const path_type& p, file_status st=file_status(),
file_status symlink_st=file_status());
void replace_filename(const path& p, file_status st=file_status(),
file_status symlink_st=file_status());
// <a href="#directory_entry-observers">observers</a>
const path& path() const;
file_status status() const;
file_status status(system::error_code& ec) const;
file_status symlink_status() const;
file_status symlink_status(system::error_code& ec) const;
bool operator< (const directory_entry& rhs);
bool operator==(const directory_entry& rhs);
bool operator!=(const directory_entry& rhs);
bool operator< (const directory_entry& rhs);
bool operator<=(const directory_entry& rhs);
bool operator> (const directory_entry& rhs);
bool operator>=(const directory_entry& rhs);
private:
path_type m_path; // for exposition only
mutable file_status m_status; // for exposition only; stat()-like
mutable file_status m_symlink_status; // for exposition only; lstat()-like
};
$NAMESPACE_END;</pre>
</div>
<p>A <code>directory_entry</code> object stores a <code>path object</code>,
a <code>file_status</code> object for non-symbolic link status, and a <code>
file_status</code> object for symbolic link status. The <code>file_status</code>
objects act as value caches.</p>
<blockquote>
<p>[<i>Note:</i> Because <code>status()</code>on a pathname may be a very expensive operation,
some operating systems provide status information as a byproduct of directory
iteration. Caching such status information can result is significant time savings. Cached and
non-cached results may differ in the presence of file system races. <i>-- end note</i>]</p>
<p><span style="background-color: #E0E0E0"><i>Actual cold-boot timing of iteration over
a directory with 15,047 entries was six seconds for non-cached status queries
versus one second for cached status queries. Windows XP, 3.0 GHz processor, with
a moderately fast hard-drive. Similar speedups are expected on Linux and BSD-derived
systems that provide status as a by-product of directory iteration.</i></span></p>
</blockquote>
<h4> <a name="directory_entry-constructors"> <code>directory_entry </code>constructors</a></h4>
<pre>directory_entry();</pre>
<blockquote>
<p><i>Postcondition:</i></p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="36%">
<tr>
<td width="18%"><b>Expression</b></td>
<td width="82%"><b>Value</b></td>
</tr>
<tr>
<td width="18%"><code>path().empty()</code></td>
<td width="82%"><code>true</code></td>
</tr>
<tr>
<td width="18%"><code>status()</code></td>
<td width="82%"><code>file_status()</code></td>
</tr>
<tr>
<td width="18%"><code>symlink_status()</code></td>
<td width="82%"><code>file_status()</code></td>
</tr>
</table>
</blockquote>
<pre>explicit directory_entry(const path_type& p, file_status st=file_status(), file_status symlink_st=file_status());</pre>
<blockquote>
<p><i>Postcondition:</i></p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="36%">
<tr>
<td width="18%"><b>Expression</b></td>
<td width="82%"><b>Value</b></td>
</tr>
<tr>
<td width="18%"><code>path()</code></td>
<td width="82%"><code>p</code></td>
</tr>
<tr>
<td width="18%"><code>status()</code></td>
<td width="82%"><code>st</code></td>
</tr>
<tr>
<td width="18%"><code>symlink_status()</code></td>
<td width="82%"><code>symlink_st</code></td>
</tr>
</table>
</blockquote>
<h4> <a name="directory_entry-modifiers"> <code>directory_entry </code>modifiers</a></h4>
<pre>void assign(const path_type& p, file_status st=file_status(), file_status symlink_st=file_status());</pre>
<blockquote>
<p><i>Postcondition:</i></p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="36%">
<tr>
<td width="18%"><b>Expression</b></td>
<td width="82%"><b>Value</b></td>
</tr>
<tr>
<td width="18%"><code>path()</code></td>
<td width="82%"><code>p</code></td>
</tr>
<tr>
<td width="18%"><code>status()</code></td>
<td width="82%"><code>st</code></td>
</tr>
<tr>
<td width="18%"><code>symlink_status()</code></td>
<td width="82%"><code>symlink_st</code></td>
</tr>
</table>
</blockquote>
<pre>void replace_filename(const path& p, file_status st=file_status(), file_status symlink_st=file_status());</pre>
<blockquote>
<p><i>Postcondition:</i></p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="43%">
<tr>
<td width="18%"><b>Expression</b></td>
<td width="82%"><b>Value</b></td>
</tr>
<tr>
<td width="18%"><code>path()</code></td>
<td width="82%"><code>path().branch() / s</code></td>
</tr>
<tr>
<td width="18%"><code>status()</code></td>
<td width="82%"><code>st</code></td>
</tr>
<tr>
<td width="18%"><code>symlink_status()</code></td>
<td width="82%"><code>symlink_st</code></td>
</tr>
</table>
</blockquote>
<h4> <a name="directory_entry-observers"> <code>directory_entry</code> observers</a></h4>
<pre>const path& path() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>m_path</code></p>
</blockquote>
<pre>file_status status() const;
file_status status(system::error_code& ec) const;</pre>
<blockquote>
<p><i>Effects:</i>
As if,</p>
<blockquote>
<pre>if ( !status_known( m_status ) )
{
if ( status_known(m_symlink_status) && !is_symlink(m_symlink_status) )
{ m_status = m_symlink_status; }
else { m_status = status(m_path<i>[, ec]</i>); }
}</pre>
</blockquote>
<p><i>Returns:</i> <code>m_status</code></p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>file_status symlink_status() const;
file_status symlink_status(system::error_code& ec) const;</pre>
<blockquote>
<p>
<i>Effects:</i>
As if,</p>
<blockquote>
<pre>if ( !status_known( m_symlink_status ) )
{
m_symlink_status = symlink_status(m_path<i>[, ec]</i>);
}</pre>
</blockquote>
<p><i>Returns:</i> <code>
m_symlink_status</code></p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>bool operator==(const directory_entry& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>m_path ==
rhs.m_path</code>.</p>
</blockquote>
<pre>bool operator!=(const directory_entry& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>m_path !=
rhs.m_path</code>.</p>
</blockquote>
<pre>bool operator< (const directory_entry& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>m_path <
rhs.m_path</code>.</p>
</blockquote>
<pre>bool operator<=(const directory_entry& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>m_path <=
rhs.m_path</code>.</p>
</blockquote>
<pre>bool operator> (const directory_entry& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>m_path >
rhs.m_path</code>.</p>
</blockquote>
<pre>bool operator>=(const directory_entry& rhs);</pre>
<blockquote>
<p><i>Returns:</i> <code>m_path >=
rhs.m_path</code>.</p>
</blockquote>
<h3><a name="Class-directory_iterator">Class <code>directory_iterator</code></a></h3>
<p>Objects of type <code>directory_iterator</code> provide standard library
compliant iteration over the contents of a directory. Also see class <code>
<a href="#Class-recursive_directory_iterator">recursive_directory_iterator</a></code>.</p>
<pre>$NAMESPACE_BEGIN;
class directory_iterator
{
public:
// <a href="#directory_iterator-members">member functions</a>
directory_iterator() noexcept; // creates the "end" iterator
directory_iterator(const directory_iterator&);
explicit directory_iterator(const path& p);
directory_iterator(const path& p, system::error_code& ec);
~directory_iterator();
directory_iterator& operator=(const directory_iterator&);
directory_iterator& operator++();
directory_iterator& increment(system::error_code& ec);
// other members as required by
// C++ Std, 24.1.1 Input iterators [input.iterators]
};
$NAMESPACE_END;</pre>
<p> <code>directory_iterator</code> satisfies the requirements of an
input iterator (C++ Std, 24.2.1, Input iterators [input.iterators]).</p>
<p>A <code>directory_iterator</code> reads successive elements from the directory for
which it was constructed, as if by calling <i>POSIX</i>
<code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/readdir_r.html">readdir_r()</a></code>. After a <code>directory_iterator</code> is constructed, and every time
<code>operator++</code> is called,
it reads a directory element and stores information about it in a object of type <code>
<a href="#Class-directory_entry">directory_entry</a></code>.
<code>operator++</code> is not equality preserving; that is, <code>i == j</code> does not imply that
<code>++i == ++j</code>. </p>
<blockquote>
<p>[<i>Note:</i> The practical consequence of not preserving equality is that directory iterators
can only be used for single-pass algorithms. <i>--end note</i>]</p>
</blockquote>
<p>If the end of the directory elements is reached, the iterator becomes equal to
the end iterator value. The constructor <code>directory_iterator()</code>
with no arguments always constructs an end iterator object, which is the only
legitimate iterator to be used for the end condition. The result of <code>
operator*</code> on an end iterator is not defined. For any other iterator value
a <code>const directory_entry&</code> is returned. The result of
<code>operator-></code> on an end iterator is not defined. For any other iterator value a <code>const directory_entry*</code> is
returned. </p>
<p>Two end iterators are always equal. An end iterator is not equal to a non-end
iterator.</p>
<blockquote>
<p><i><span style="background-color: #E0E0E0">The above wording is based on the
Standard Library's istream_iterator wording.</span></i></p>
</blockquote>
<p>The result of calling the <code>path()</code> member of the <code>
directory_entry</code> object obtained by dereferencing a <code>
directory_iterator</code> is a reference to a <code>path</code>
object composed of the directory argument from which the iterator was
constructed with filename of the directory entry appended as if by <code>
operator/=</code>. </p>
<p>Directory iteration shall not yield directory entries for the current (<i>dot</i>)
and parent (<i>dot dot</i>) directories.</p>
<p>The order of directory entries obtained by dereferencing successive
increments of a <code>directory_iterator</code> is unspecified.</p>
<blockquote>
<p>[<i>Note:</i> Programs performing directory iteration may wish to test if the
path obtained by dereferencing a directory iterator actually exists. It could be
a
symbolic link to a non-existent file. Programs recursively
walking directory trees for purposes of removing and renaming entries may wish
to avoid following symbolic links.</p>
<p>If a file is removed from or added to a directory after the
construction of a <code>directory_iterator</code> for the directory, it is
unspecified whether or not subsequent incrementing of the iterator will ever
result in an iterator whose value is the removed or added directory entry. See
<i>POSIX</i>
<code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/readdir_r.html">readdir_r()</a></code>. <i>
--end note</i>]</p>
</blockquote>
<h4><a name="directory_iterator-members"><code>directory_iterator</code> members</a></h4>
<p><code><a name="directory_iterator-default-ctor">directory_iterator</a>()
noexcept;</code></p>
<blockquote>
<p><i>Effects:</i> Constructs the end iterator.</p>
</blockquote>
<pre><code>explicit <a name="directory_iterator-ctor-path">directory_iterator</a>(</code>const path& p<code>);
directory_iterator(</code>const path& p, system::error_code& ec<code>);</code></pre>
<blockquote>
<p><i>Effects:</i> Constructs a iterator representing the first
entry in the directory <code>p</code> resolves to, if any; otherwise, the end iterator.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p>[<i>Note:</i> To iterate over the current directory, use <code>
directory_iterator(".")</code> rather than <code>directory_iterator("")</code>.
<i>-- end note</i>]</p>
</blockquote>
<pre>directory_iterator& <a name="directory_iterator-increment">operator++</a>();
directory_iterator& increment(system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i> As specified by the C++ Standard, 24.1.1 Input iterators [input.iterators]</p>
<p><i>Returns:</i> <code>*this</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<h3><a name="Class-recursive_directory_iterator">Class <code>recursive_directory_iterator</code></a></h3>
<p>Objects of type <code>recursive_directory_iterator</code> provide standard library
compliant iteration over the contents of a directory, including recursion into
its sub-directories.</p>
<pre>$NAMESPACE_BEGIN;
class recursive_directory_iterator :
public iterator<input_iterator_tag, directory_entry>
{
public:
// constructors and destructor
recursive_directory_iterator() noexcept;
recursive_directory_iterator(const recursive_directory_iterator&);
explicit recursive_directory_iterator(const path& p,
<a href="#symlink_option">symlink_option</a> opt = symlink_option::none);
recursive_directory_iterator(const path& p,
<a href="#symlink_option">symlink_option</a> opt, system::error_code& ec);
recursive_directory_iterator(const path& p, system::error_code& ec);
~recursive_directory_iterator();
// observers
int level() const noexcept;
bool no_push<code>_pending</code>() const noexcept;
// modifiers
recursive_directory_iterator& operator=(const recursive_directory_iterator&);
recursive_directory_iterator& operator++();
recursive_directory_iterator& increment(system::error_code& ec);
void pop();
void no_push(bool value=true);
// other members as required by
// C++ Std, Input iterators [input.iterators]
private:
<i><b> // actual data members will probably be stored in a shared object,
// or some similar mechanism, to achieve the required input iterator
// copy semantics
</b></i> int m_level; <b><i> // for exposition only</i></b>
bool m_no_<code>push</code>; <i><b>// for exposition only
</b></i><a href="#symlink_option">symlink_option</a> m_options; <i><b>// for exposition only</b></i>
};
$NAMESPACE_END;</pre>
<p>The behavior of a <code>recursive_directory_iterator</code> is the same
as a <code>directory_iterator</code> unless otherwise specified.</p>
<ul>
<li>Incrementing a <code>recursive_directory_iterator</code> pointing to a
directory causes that directory itself to be iterated ovee, as specified by
the <code>operator++</code> and <code>increment</code> functions.<br>
</li>
<li>When a <code>recursive_directory_iterator</code> reaches the end of the directory currently being iterated
over, or when <code>pop()</code> is called, <code>m_level</code> is
decremented, and iteration of the parent directory continues.</li>
</ul>
<pre>recursive_directory_iterator() noexcept;</pre>
<blockquote>
<p><i>Effects:</i> Constructs the end iterator.</p>
</blockquote>
<pre>explicit recursive_directory_iterator(const path& p, <a href="#symlink_option">symlink_option</a> opt = symlink_option::none);
recursive_directory_iterator(const path& p, <a href="#symlink_option">symlink_option</a> opt, system::error_code& ec);
recursive_<code>directory_iterator(</code>const path& p, system::error_code& ec<code>);</code></pre>
<blockquote>
<p><i>Effects:</i> Constructs a iterator representing the first
entry in the directory <code>p</code> resolves to, if any; otherwise, the end iterator.</p>
<p dir="ltr"><i>Postcondition: </i>Unless the end iterator was constructed,<i> </i>
<code>level() == 0 && no_push_pending() == false && m_options == opt</code>.
For the signature without a <code>symlink_option</code> argument, <code>opt</code>
is assumed to be <code>symlink_option::none</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p>[<i>Note:</i> To iterate over the current directory, use <code>recursive_directory_iterator(".")</code> rather than
<code>recursive_directory_iterator("")</code>.
<i>-- end note</i>]</p>
<p>[<i>Note:</i> By default, <code>recursive_directory_iterator</code> does not
follow directory symlinks. To follow directory symlinks, specify <code>opt</code>
as <code>symlink_option::recurse</code>
<i>-- end note</i>]</p>
</blockquote>
<pre>int level() const noexcept;</pre>
<blockquote>
<p><i>Requires:</i> <code>*this != recursive_directory_iterator()</code>.</p>
<p><i>Returns:</i> <code>m_level</code>.</p>
</blockquote>
<pre>bool <code>no_push_pending</code>() const noexcept;</pre>
<blockquote>
<p><i>Requires:</i> <code>*this != recursive_directory_iterator()</code>.</p>
<p><i>Returns:</i> <code>m_no_push</code>.</p>
</blockquote>
<pre><code>recursive_directory_iterator</code>& <a name="recursive_directory_iterator-increment">operator++</a>();
recursive_directory_iterator& increment(system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i> As specified by the C++ Standard, 24.1.1 Input iterators [input.iterators],
except:</p>
<ul>
<li dir="ltr">
<p dir="ltr">if <code>!no_push_pending() && is_directory(this->status())
&& (!is_symlink(this->symlink_status()) || (m_options
& symlink_option::recurse) != 0)</code> then <code>m_level</code>
is incremented and directory <code>(*this)->path()</code> is recursively iterated into.<br>
</p>
</li>
<li>if there are no more directory entries at this level then <code>m_level</code>
is decremented and iteration of the parent directory resumes.</li>
</ul>
<p><i>Postcondition:</i> <code>no_push_pending() == false</code>.</p>
<p><i>Returns:</i> <code>*this</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>void pop();</pre>
<blockquote>
<p><i>Requires:</i> <code>*this != recursive_directory_iterator()</code>.</p>
<p><i>Effects:</i> If <code>level() == 0</code>, set <code>*this</code> to <code>recursive_directory_iterator()</code>.
Otherwise, <code>--m_level</code>, cease iteration of the directory currently being
iterated over, and continue iteration over the parent directory.</p>
</blockquote>
<pre>void no_push(bool value=true);</pre>
<blockquote>
<p><i>Requires:</i> <code>*this != recursive_directory_iterator()</code>.</p>
<p><i>Postcondition:</i> <code>no_push_pending() == value</code>.</p>
<p>[<i>Note:</i> <code>no_push()</code> is used to prevent
unwanted recursion into a directory. <i>--end note</i>]</p>
</blockquote>
<h3><a name="Operational-functions">Operational functions</a></h3>
<p>Operational functions query or modify files, including directories, in external
storage.</p>
<p>Operational functions access a file by resolving an
object of class <code>path</code> to a particular file in a file hierarchy. The
path is resolved as if by the <i>POSIX</i>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap04.html#tag_04_11">
Pathname Resolution</a> mechanism.</p>
<p>[<i>Note: </i>Because hardware failures, network failures,
<a href="#Race-condition">file system races</a>, and many
other kinds of errors occur frequently in file system operations, users should be aware
that any filesystem operational function, no matter how apparently innocuous, may encounter
an error. See <a href="#Error-reporting">Error reporting</a>. <i>-- end note</i>]</p>
<h4><a name="Function-specifications">Operational function specifications</a></h4>
<pre>path <a name="absolute">absolute</a>(const path& p, const path& base=current_path());</pre>
<blockquote>
<p><i>Returns:</i> A <a href="#Absolute-path">absolute path</a> composed according to the
following table</p>
<table border="1" cellpadding="5" cellspacing="0" bordercolor="#111111" style="border-collapse: collapse">
<tr>
<td align="center"> </td>
<td align="center"><b><code>p.has_root_directory()</code></b></td>
<td align="center"><b><code>!p.has_root_directory()</code></b></td>
</tr>
<tr>
<td align="center"><b><code>p.has_root_name()</code></b></td>
<td align="center"><code>return p</code></td>
<td align="center"><code>return p.root_name() /
absolute(base).root_directory()<br>
/ absolute(base).relative_path() / p.relative_path()</code></td>
</tr>
<tr>
<td align="center"><b><code>!p.has_root_name()</code></b></td>
<td align="center"><code>return absolute(base).root_name()<br>
/ p</code></td>
<td align="center"><code>return absolute(base) / p</code></td>
</tr>
</table>
<p dir="ltr">[<i>Note:</i> For the returned path, <code>rp,</code> <code>
rp.is_absolute()</code> is true. <i>-- end note</i>]</p>
<p><i>Throws:</i> If <code>base.is_absolute()</code> is true, throws only if
memory allocation fails.</p>
</blockquote>
<pre>path <a name="canonical">canonical</a>(const path& p, const path& base = current_path());
path canonical(const path& p, system::error_code& ec);
path canonical(const path& p, const path& base, system::error_code& ec);</pre>
<blockquote>
<p><i>Overview:</i> Converts <code>p</code>, which must exist, to an absolute
path that has no symbolic link, <a href="#Dot">dot</a>,
or <a href="#Dot">dot-dot</a> elements. </p>
<p><i>Returns:</i> A <a href="#Canonical-path">canonical path</a> that refers to
the same file system object as <code>absolute(p,base)</code>. For the overload
without a <code>base</code> argument, <code>base</code> is <code>current_path()</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p><i>Remarks:</i> <code>!exists(p)</code> is an error.</p>
<p>[<i>Note:</i> Canonical pathnames allow security checking of a path (eg.
does this path live in /home/goodguy or /home/badguy?) -- end note]</p>
</blockquote>
<pre>void <a name="copy">copy</a>(const path& from, const path& to);
void copy(const path& from, const path& to, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i> As if</p>
<blockquote>
<pre>file_status s(symlink_status(from<i>[</i><code>, ec</code><i>]</i>));
if(is_symlink(s))
copy_symlink(from, to<i>[</i><code>, ec</code><i>]</i>);
else if(is_directory(s))
copy_directory(from, to<i>[</i><code>, ec</code><i>]</i>);
else if(is_regular_file(s))
copy_file(from, to, copy_option::fail_if_exists<i>[</i><code>, ec</code><i>]</i>);
else
<i> Report error as specified in <a href="#Error-reporting">Error reporting</a>.</i></pre>
</blockquote>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>void <a name="copy_directory">copy_directory</a>(const path& from, const path& to);
void copy_directory(const path& from, const path& to, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects: </i></p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>void copy_file(const path& from, const path& to);
void copy_file(const path& from, const path& to, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects: </i><code>copy_file(from, to,
copy_option::fail_if_exists</code><i>[</i><code>, ec</code><i>]</i><code>)</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>void <a name="copy_file">copy_file</a>(const path& from, const path& to, <a href="#copy_option">copy_option</a> option);
void <a name="copy_file2">copy_file</a>(const path& from, const path& to, <a href="#copy_option">copy_option</a> option, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i> If <code>option == copy_option::</code><code>fail_if_exists
&& exists(to)</code>, an error is reported. Otherwise, the contents and attributes of the file <code>from</code>
resolves to are copied to the file <code>to</code> resolves to.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>void <a name="copy_symlink">copy_symlink</a>(const path& existing_symlink, const path& new_symlink);
void copy_symlink(const path& existing_symlink, const path& new_symlink, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects: </i><code>create_symlink(read_symlink(existing_symlink</code><i>[</i><code>, ec</code><i>]</i><code>),
new_symlink</code><i>[</i><code>, ec</code><i>]</i><code>)</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>bool <a name="create_directories">create_directories</a>(const path& p);
bool <a name="create_directories2">create_directories</a>(const path& p, system::error_code& ec);</pre>
<blockquote>
<p><i>Requires:</i> <code>p.empty() || <br>
forall px: px == p || is_parent(px, p): is_directory(px) || !exists( px )</code>
</p>
<p><i>Postcondition:</i> <code>is_directory(p)</code></p>
<p><i>Returns:</i> The value of <code>!exists(p)</code> prior to the
establishment of the postcondition.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>bool <a name="create_directory">create_directory</a>(const path& p);
bool <a name="create_directory2">create_directory</a>(const path& p, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i> Attempts to create the directory <code>p</code> resolves to,
as if by<i> POSIX </i><code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/mkdir.html">mkdir()</a></code> with a second argument of S_IRWXU|S_IRWXG|S_IRWXO. </p>
<p><i>Postcondition:</i> <code>is_directory(p)</code></p>
<p><i>Returns:</i> <code>true</code> if a new directory was created, otherwise
<code>false</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>void <a name="create_directory_symlink">create_directory_symlink</a>(const path& to, const path& new_symlink);
void create_directory_symlink(const path& to, const path& new_symlink, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i>
Establishes the postcondition, as if by <i>
POSIX</i>
<code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/symlink.html">
symlink()</a></code>.</p>
<p><i>
Postcondition:</i> <code>new_symlink</code> resolves to a symbolic link file that
contains an unspecified representation of <code>to</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p dir="ltr">[<i>Note:</i>
Some operating systems, such as Windows, require symlink creation to
identify that the link is to a directory. Portable code should use <code>
create_directory_symlink()</code> to create directory symlinks rather than
<code>create_symlink()</code> <i>-- end note</i>]</p>
<p>[<i>Note:</i>
Some operating systems do not support symbolic links at all or support
them only for regular files.
Some file systems do not
support
symbolic links regardless of the operating system - the FAT file system used on
memory cards and flash drives, for example. <i>-- end note</i>]</p>
</blockquote>
<pre>void <a name="create_hard_link">create_hard_link</a>(const path& to, const path& new_hard_link);
void <a name="create_hard_link2">create_hard_link</a>(const path& to, const path& new_hard_link, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i> Establishes the postcondition, as if by
<i>POSIX</i>
<code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/link.html">
link()</a></code>.</p>
<p><i>Postcondition:</i></p>
<ul>
<li> <code>exists(to) &&
exists(</code><code>new_hard_link</code><code>) && equivalent(to,
</code><code>new_hard_link</code><code>)</code></li>
<li>The contents of the file or directory
<code>to</code> resolves to are unchanged.</li>
</ul>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p>[<i>Note:</i>
Some operating systems do not support hard links at all or support
them only for regular files. Some file systems do not support hard
links regardless of the operating system - the FAT file system used on memory
cards and flash drives, for example. Some file systems limit the number of
links per file. <i>-- end note</i>]</p>
</blockquote>
<pre>void <a name="create_symlink">create_symlink</a>(const path& to, const path& new_symlink);
void <a name="create_symlink2">create_symlink</a>(const path& to, const path& new_symlink, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i>
Establishes the postcondition, as if by <i>
POSIX</i>
<code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/symlink.html">
symlink()</a></code>.</p>
<p><i>
Postcondition:</i> <code>new_symlink</code> resolves to a symbolic link file that
contains an unspecified representation of <code>to</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p>[<i>Note:</i>
Some operating systems do not support symbolic links at all or support
them only for regular files.
Some file systems do not
support
symbolic links regardless of the operating system - the FAT system used on
memory cards and flash drives, for example. <i>-- end note</i>]</p>
</blockquote>
<pre>path <a name="current_path">current_path</a>();
path <a name="current_path2">current_path</a>(system::error_code& ec);</pre>
<blockquote>
<p><i>Returns:</i> The current working directory path, as if by <i>POSIX</i>
<code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/getcwd.html">
getcwd()</a></code>. <code>is_absolute()</code> is true for the returned path.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p>[<i>Note: </i>The <code>
current_path()</code> name was chosen to emphasize that the return is a
path, not just a single directory name.</p>
<p>The current path as returned by many operating systems is a dangerous
global variable. It may be changed unexpectedly by a third-party or system
library functions, or by another thread. <i>-- end note</i>]</p>
</blockquote>
<pre>void current_path(const path& p);
void current_path(const path& p, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i>
Establishes the postcondition, as if by <i>
POSIX</i>
<code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/chdir.html">
chdir()</a></code>.</p>
<p><i>Postcondition:</i> <code>equivalent(p, current_path())</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p>[<i>Note: </i>The current path for many operating systems is a dangerous
global state. It may be changed unexpectedly by a third-party or system
library functions, or by another thread. <i>-- end note</i>]</p>
</blockquote>
<pre>bool <a name="exists">exists</a>(file_status s) noexcept;</pre>
<blockquote>
<p><i>Returns:</i>
<code>status_known(s) && s.type() != file_not_found</code></p>
</blockquote>
<pre>bool <a name="exists2">exists</a>(const path& p);
bool <a name="exists3">exists</a>(const path& p, system::error_code& ec) noexcept;</pre>
<blockquote>
<p><i>Returns:</i> <code>exists(status(p))</code> or <code>exists(status(p, ec))</code>,
respectively.</p>
<p><i>Throws:</i> <code>filesystem_error</code>; overload with <code>error_code&</code> throws
nothing.</p>
</blockquote>
<pre><code>bool <a name="equivalent">equivalent</a>(const path& p1, const path& p2);
bool <a name="equivalent2">equivalent</a>(const path& p1, const path& p2, system::error_code& ec);</code></pre>
<blockquote>
<p><i>Effects:</i> Determines <code>file_status s1</code>
and <code>s2</code>, as if by <code>status(p1)</code> and <code>status(p2)</code>,
respectively.</p>
<p><i>Returns:</i> <code>true</code>, if <code>sf1 ==
sf2</code> and <code>p1</code> and <code>p2</code> resolve to the same file
system entity, else <code>false</code>.</p>
<blockquote>
<p>Two paths are considered to resolve to the same
file system entity if two candidate entities reside on the same device at the
same location. This is determined as if by the values of the <i>POSIX</i>
<code>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">
stat</a></code> structure<code>,</code> obtained as if by <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/stat.html">
stat()</a></code> for the two paths, having equal <code>st_dev</code> values
and equal <code>st_ino</code> values.</p>
<p>[<i>Note:</i> <i>POSIX</i> requires that <i>"st_dev</i>
must be unique within a Local Area Network". Conservative <i>POSIX</i>
implementations may also wish to check for equal <code>st_size</code> and
<code>st_mtime</code> values. <i>Windows</i> implementations may use <code>
GetFileInformationByHandle()</code> as a surrogate for <code>stat()</code>,
and consider "same" to be equal values for <code>dwVolumeSerialNumber</code>,
<code>nFileIndexHigh</code>, <code>nFileIndexLow</code>, <code>nFileSizeHigh</code>,
<code>nFileSizeLow</code>, <code>ftLastWriteTime.dwLowDateTime</code>, and
<code>ftLastWriteTime.dwHighDateTime</code>. <i>-- end note</i>]</p>
</blockquote>
<p><i>Throws:</i> <code>filesystem_error</code>
if <code>(!exists(s1) && !exists(s2)) || (is_other(s1) && is_other(s2))</code>,
otherwise as specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<div dir="ltr">
<pre>uintmax_t <a name="file_size">file_size</a>(const path& p);
uintmax_t <a name="file_size2">file_size</a>(const path& p, system::error_code& ec);</pre>
</div>
<blockquote>
<p><i>Returns:</i> If <code>exists(p) && is_regular_file(p)</code>, the size
in bytes
of the file <code>p</code> resolves to, determined as if by the value of
the <i>POSIX</i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">stat</a></code> structure member <code>st_size</code>
obtained as if by <i>POSIX</i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/stat.html">stat()</a></code>.
Otherwise, <code>static_cast<uintmax_t>(-1)</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>uintmax_t <a name="hard_link_count">hard_link_count</a>(const path& p);
uintmax_t hard_link_count(const path& p, system::error_code& ec);</pre>
<blockquote>
<p><i>Returns:</i> The number of hard links for <code>p</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>const path& <a name="initial_path">initial_path</a>();
const path& <a name="initial_path">initial_path</a>(<code>system::error_code& ec</code>);</pre>
<blockquote>
<p><i>Returns:</i>
<code>current_path()</code> as of the first call to <code>initial_path()</code>.</p>
<p>[<i>Note:</i> <code>
initial_path()</code> is not thread safe, and may return an undesirable result
if called subsequent to a change to the current directory. These problems can
be avoided by calling <code>initial_path()</code> immediately on entry to
main(). <i>--end note</i>]</p>
<p><i>Throws:</i> For the first call, as specified in
<a href="#Error-reporting">
Error reporting</a>. Subsequent calls throw nothing.</p>
</blockquote>
<pre>bool <code><a name="is_directory">is_directory</a></code>(file_status s) noexcept;</pre>
<blockquote>
<p><i>Returns:</i>
<code>s.type() == directory_file</code></p>
</blockquote>
<pre><code>bool <a name="is_directory2">is_directory</a>(const path& p);
bool <a name="is_directory3">is_directory</a>(const path& p, system::error_code& ec) noexcept;</code></pre>
<blockquote>
<p dir="ltr"><i>Returns:</i> <code>is_directory(status(p))</code> or <code>is_directory(status(p, ec))</code>,
respectively.</p>
<p><i>Throws:</i> <code>filesystem_error</code>; overload with <code>error_code&</code> throws
nothing.</p>
</blockquote>
<pre><code>bool <a name="is_empty">is_empty</a>(const path& p);
bool <a name="is_empty2">is_empty</a></a>(const path& p, system::error_code& ec);</code></pre>
<blockquote>
<p><i>Effects:</i> Determines <code>file_status s</code>, as if by <code>
status(p, ec)</code>.</p>
<p><i>Returns:</i> <code>is_directory(s)<br>
?
directory_iterator(p) == directory_iterator()<br>
: file_size(p) == 0;</code></p>
</blockquote>
<pre>bool <code><a name="is_regular_file">is_regular_file</a></code>(file_status s) noexcept;</pre>
<blockquote>
<p><i>Returns:</i>
<code>s.type() == regular_file</code></p>
</blockquote>
<pre><code>bool <a name="is_regular_file2">is_regular_file</a>(const path& p);</code></pre>
<blockquote>
<p><i>Returns:</i> <code>is_regular_file(status(p))</code>.</p>
<p><i>Throws:</i> <code>filesystem_error</code>
if <code>status(p)</code> would throw <code>filesystem_error.</code></p>
</blockquote>
<pre><code>bool <a name="is_regular_file3">is_regular_file</a>(const path& p, system::error_code& ec) noexcept;</code></pre>
<blockquote>
<p><i>Effects:</i> Sets <code>ec</code> as if by <code>status(p, ec)</code>. [<i>Note:</i>
<code>status_error</code>,
<code>file_not_found</code>
and
<code>type_unknown</code>
cases set <code>ec</code>
to error values. To distinguish between cases, call the <code>
status</code>
function directly. <i>-- end
note</i>] </p>
<p><i>Returns:</i> <code>is_regular_file(status(p, ec))</code>.</p>
</blockquote>
<pre>bool <a name="is_other">is_other</a>(file_status s) noexcept;</pre>
<blockquote>
<p><i>Returns:</i>
<code>return exists(s) && !is_regular_file(s) && !is_directory(s) && !is_symlink(s)</code></p>
</blockquote>
<pre><code>bool <a name="is_other2">is_other</a>(const path& p);
bool <a name="is_other3">is_other</a>(const path& p, system::error_code& ec) noexcept;</code></pre>
<blockquote>
<p><i>Returns:</i> <code>is_other(status(p))</code> or <code>is_other(status(p, ec))</code>,
respectively.</p>
<p><i>Throws:</i> <code>filesystem_error</code>; overload with <code>error_code&</code> throws
nothing.</p>
</blockquote>
<pre>bool <a name="is_symlink">is_symlink</a>(file_status s) noexcept;</pre>
<blockquote>
<p><i>Returns:</i>
<code>s.type() == symlink_file</code></p>
</blockquote>
<pre><code>bool <a name="is_symlink2">is_symlink</a>(const path& p);
bool <a name="is_symlink3">is_symlink</a>(const path& p, system::error_code& ec) noexcept;</code></pre>
<blockquote>
<p><i>Returns:</i> <code>is_symlink(symlink_status(p))</code> or <code>is_symlink(symlink_status(p, ec))</code>,
respectively.</p>
<p><i>Throws:</i> <code>filesystem_error</code>; overload with <code>error_code&</code> throws
nothing.</p>
</blockquote>
<pre>std::time_t <a name="last_write_time">last_write_time</a>(const path& p);
std::time_t <a name="last_write_time2">last_write_time</a>(const path& p<code>, system::error_code& ec</code>);</pre>
<blockquote>
<p><i>Returns:</i> The time of last data modification of <code>p</code>, determined as if by the
value of the <i>POSIX</i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">stat</a></code> structure member <code>st_mtime</code> obtained
as if by <i>POSIX</i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/stat.html">stat()</a></code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>void <a name="last_write_time3">last_write_time</a>(const path& p, const std::time_t new_time);
void <a name="last_write_time4">last_write_time</a>(const path& p, const std::time_t new_time<code>, system::error_code& ec</code>);</pre>
<blockquote>
<p><i>Effects:</i> Sets the time of last data modification of the file
resolved to by <code>p</code>
to <code>new_time</code>, as if by <i>POSIX</i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/stat.html">stat()</a></code>
followed by <i>POSIX</i>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/utime.html">
<code>utime()</code></a>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p>[<i>Note:</i> A postcondition of <code>last_write_time(p) ==
new_time</code> is not specified since it might not hold for file systems
with coarse time granularity. <i>-- end note</i>]</p>
</blockquote>
<pre>void <a name="permissions">permissions</a>(const path& p, <a href="#symlink_perms">perms</a> prms);
void permissions(const path& p, <a href="#symlink_perms">perms</a> prms, system::error_code& ec);</pre>
<blockquote>
<p dir="ltr">
<i>Requires:</i> <code>!((prms & add_perms) && (prms & remove_perms))</code>.</p>
<p dir="ltr"><i>Effects:</i> Applies the effective permissions bits from <code>
prms</code> to the file <code>p</code> resolves to, as if by <i>POSIX</i>
<code>
<a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/fchmodat.html">
fchmodat()</a></code>. The effective permission bits are determined as
specified by the following table. </p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111">
<tr>
<td><b>bits present in <code>prms</code></b></td>
<td><b>Effective bits applied</b></td>
</tr>
<tr>
<td>Neither <code>add_perms</code> nor <code>remove_perms</code></td>
<td><code>prms & perms_mask</code></td>
</tr>
<tr>
<td><code>add_perms</code></td>
<td>
<p dir="ltr"><code>status(p).permissions() | (prms &
<a href="#perms_mask">perms_mask</a>)</code>
</td>
</tr>
<tr>
<td><code>remove_perms</code></td>
<td><code>status(p)</code><code>.permissions() & ~(prms &
<a href="#perms_mask">perms_mask</a>)
</code> </td>
</tr>
</table>
<p>[<i>Note:</i> Conceptually permissions are viewed as bits, but the actual
implementation may use some other mechanism. -- <i>end note</i>]</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>path <a name="read_symlink">read_symlink</a>(const path& p);
path read_symlink(const path& p, system::error_code& ec);</pre>
<blockquote>
<p dir="ltr"><i>Returns:</i> If <code>p</code> resolves to a symbolic
link, a <code>path</code> object containing the contents of that symbolic
link. Otherwise an empty <code>path</code> object.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>. [<i>Note:</i> It is an error if <code>p</code> does not
resolve to a symbolic link. <i>-- end note</i>]</p>
</blockquote>
<pre>bool <a name="remove">remove</a>(const path& p);
bool <a name="remove2">remove</a>(const path& p, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i> If <code>exists(symlink_status(p,ec))</code>, it is
removed
as if by<i> POSIX </i><code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/remove.html">remove()</a></code>.</p>
<blockquote>
<p>[<i>Note:</i> A symbolic link is itself removed, rather than the file it
resolves to being removed. <i>-- end note</i>]</p>
</blockquote>
<p><i>Postcondition:</i> <code>!exists(symlink_status(p))</code>.</p>
<p><i>Returns:</i> <code>false</code> if p did not exist in the first
place, otherwise <code>true</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>uintmax_t <a name="remove_all">remove_all</a>(const path& p);
uintmax_t <a name="remove_all2">remove_all</a>(const path& p, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i> Recursively deletes the contents of p if it exists,
then deletes file <code>p</code> itself,
as if by<i> POSIX </i><code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/remove.html">remove()</a></code>.</p>
<blockquote>
<p>[<i>Note:</i> A symbolic link is itself removed, rather than the file it
resolves to being removed. <i>-- end note</i>]</p>
</blockquote>
<p><i>Postcondition:</i> <code>!exists(p)</code></p>
<p><i>Returns:</i> The number of files removed.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>void <a name="rename">rename</a>(const path& old_p, const path& new_p);
void <a name="rename2">rename</a>(const path& old_p, const path& new_p, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i> Renames <code>old_p</code> to <code>new_p</code>, as if by
<i>POSIX</i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/rename.html">
rename()</a></code>.</p>
<blockquote>
<p>[<i>Note:</i> If <code>old_p</code> and <code>new_p</code> resolve to the
same existing file, no action is taken. Otherwise, if <code>new_p</code> resolves to an
existing non-directory file, it is removed, while if <code>new_p</code> resolves to an
existing directory, it is removed if empty on POSIX but is an error on Windows. A symbolic link is itself renamed, rather than
the file it resolves to being renamed. <i>-- end note</i>]</p>
</blockquote>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre>void <a name="resize_file">resize_file</a>(const path& p, uintmax_t new_size);
void <a name="resize_file2">resize_file</a>(const path& p, uintmax_t new_size, system::error_code& ec);</pre>
<blockquote>
<p><i>Postcondition:</i> <code>file_size() == new_size</code>.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p><i>Remarks:</i> Achieves its postconditions as if by
POSIX <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/truncate.html">
truncate()</a></code>.</p>
</blockquote>
<pre>space_info <a name="space">space</a>(const path& p);
space_info <a name="space2">space</a>(const path& p, system::error_code& ec);</pre>
<blockquote>
<p><i>Returns:</i> An object of type <code>
<a href="#space_info">space_info</a></code>. The value of the <code>space_info</code> object is determined as if by
using <i>POSIX</i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/statvfs.html" style="text-decoration: none">
statvfs()</a></code> to obtain a <i>POSIX</i> struct <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/statvfs.h.html" style="text-decoration: none">
statvfs</a></code>, and then multiplying its <code>f_blocks</code>, <code>
f_bfree</code>, and <code>f_bavail</code> members by its <code>f_frsize</code>
member, and assigning the results to the <code>capacity</code>, <code>free</code>,
and <code>available</code> members respectively. Any members for which the
value cannot be determined shall be set to -1.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
</blockquote>
<pre><a href="#file_status">file_status</a> <a name="status">status</a>(const path& p);</pre>
<blockquote>
<p><i>Effects: </i>As if:</p>
<blockquote>
<pre>system::error_code ec;
file_status result = status(p, ec);
if (result == status_error)
throw filesystem_error(<i>implementation-supplied-message</i>, p, ec);
return result;</pre>
</blockquote>
<p><i>Returns:</i> See above.</p>
<p><i>Throws:</i> <code>filesystem_error</code>.
[<i>Note:</i> <code>result</code> values of <code>
file_status(file_not_found)</code>and <code>
file_status(type_unknown)</code> are not considered failures and do not
cause an exception to be
thrown.<i> -- end note</i>] </p>
</blockquote>
<pre><a href="#file_status">file_status</a> <a name="status2">status</a>(const path& p, system::error_code& ec) noexcept;</pre>
<blockquote>
<p><i>Effects: </i></p>
<blockquote>
<p>If possible, determines the attributes
of the file
<code>p</code> resolves to, as if by<i> POSIX </i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/stat.html">stat()</a></code>.</p>
If, during attribute determination, the underlying file system API reports
an error, sets <code>ec</code> to indicate the specific error reported.
Otherwise, <code>ec.clear()</code>.<blockquote>
<p>[<i>Note:</i> This allows users to inspect the specifics of underlying
API errors even when the value returned by <code>status()</code> is not <code>
file_status(status_error)</code>. <i>--end note</i>]</p>
</blockquote>
</blockquote>
<p><i>Returns:</i></p>
<blockquote>
<p>If <code>ec != error_code()</code>:</p>
<ul>
<li>If the specific error indicates that <code>p</code> cannot be resolved
because some element of the path does not exist, return <code>
file_status(file_not_found)</code>. [<i>Note:</i> POSIX errors that
indicate this are ENOENT or ENOTDIR. Windows equivalents
include ERROR_FILE_NOT_FOUND, ERROR_PATH_NOT_FOUND, ERROR_INVALID_NAME,
ERROR_INVALID_PARAMETER, ERROR_BAD_PATHNAME, and ERROR_BAD_NETPATH. <i>--
end note</i>]<br>
</li>
<li>Otherwise, if the specific error indicates that <code>p</code> can be resolved
but the attributes cannot be determined, return <code>
file_status(type_unknown)</code>. [<i>Note: </i>For example, Windows
ERROR_SHARING_VIOLATION errors. For POSIX, the case never arises. <i>-- end
note</i>]<br>
</li>
<li>Otherwise, return <code>
file_status(status_error)</code>.</li>
</ul>
<blockquote>
<p>[<i>Note:</i> These semantics distinguish between
<code>p</code> being known not to exist,
<code>p</code> existing but not being able to determine its attributes,
and there being an error that prevents even knowing if
<code>p</code> exists. These
distinctions are important to some use cases. <i>--end note</i>]</p>
</blockquote>
<p>Otherwise,</p>
<ul>
<li>If the attributes indicate a regular file, as if by <i>POSIX</i> <a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">S_ISREG()</a>,
return <code>
file_status(regular_file)</code>. [<i>Note:</i> <code>
regular_file</code> implies appropriate <code><fstream></code> operations
would succeed, assuming no hardware, permission, access, or file system
race
errors. Lack of
<code>regular_file</code> does not necessarily imply <code><fstream></code> operations would
fail on a directory.
<i>-- end note</i>]<br>
</li>
<li>Otherwise, if the attributes indicate a directory, as if by <i>POSIX</i>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">S_ISDIR()</a>,
return <code>
file_status(directory_file)</code>. [<i>Note:</i> <code>directory_file</code> implies <code>
directory_iterator(p)</code>would succeed.
<i>-- end note</i>]<br>
</li>
<li>Otherwise, if the attributes indicate a block special file, as if by <i>POSIX</i>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">S_ISBLK()</a>,
return <code>
file_status(block_file)</code>.<br>
</li>
<li>Otherwise, if the attributes indicate a character special file, as if by <i>POSIX</i>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">S_ISCHR()</a>,
return <code>
file_status(character_file)</code>.<br>
</li>
<li>Otherwise, if the attributes indicate a fifo or pipe file, as if by <i>POSIX</i>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">S_ISFIFO()</a>,
return <code>
file_status(fifo_file)</code>.<br>
</li>
<li>Otherwise, if the attributes indicate a socket, as if by <i>POSIX</i>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">S_ISSOCK()</a>,
return <code>
file_status(socket_file)</code>.<br>
</li>
<li>Otherwise, return <code>
file_status(type_unknown)</code>.</li>
</ul>
</blockquote>
<p><i>Remarks:</i> If a symbolic link is encountered during pathname
resolution,
pathname resolution continues using the contents of the symbolic link.</p>
</blockquote>
<pre>bool <a name="status_known">status_known</a>(file_status s) noexcept;</pre>
<blockquote>
<p><i>Returns:</i>
<code>s.type() != status_error</code></p>
</blockquote>
<pre>file_status <a name="symlink_status">symlink_status</a>(const path& p);
file_status <a name="symlink_status2">symlink_status</a>(const path& p, system::error_code& ec) noexcept;</pre>
<blockquote>
<p><i>Effects:</i> Same as <a href="#status">status()</a>, above,
except that the attributes
of
<code>p</code> are determined as if by<i> POSIX </i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/lstat.html">
lstat()</a></code>.</p>
</blockquote>
<blockquote>
<p><i>Returns:</i> Same as <a href="#status">status()</a>, above, except
that if the attributes indicate a symbolic link, as if by <i>POSIX</i>
<a class="external" href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">
S_ISLNK()</a>, return <code>file_status(symlink_file)</code>.</p>
<p><i>Remarks:</i> Pathname resolution terminates if <code>p</code> names a symbolic link.</p>
<p><i>Throws:</i> <code>filesystem_error</code>; overload with <code>error_code&</code> throws
nothing.</p>
</blockquote>
<pre>path <a name="system_complete">system_complete</a>(const path& p);
path <a name="system_complete2">system_complete</a>(const path& p, system::error_code& ec);</pre>
<blockquote>
<p><i>Effects:</i> Composes an absolute path from <code>p</code>, using the
same rules used by the operating system to resolve a path passed as the
filename argument to standard library open functions.</p>
<p><i>Returns:</i> The composed path.</p>
<p><i>Postcondition:</i> For the returned path, <code>rp,</code> <code>
rp.is_absolute()</code> is true.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p>[<i>Note:</i> For <i>POSIX</i>, <code>system_complete(p)</code> has the same semantics as
<code>complete(p, current_path())</code>.</p>
<p><a name="windows_effects">For <i>Windows</i></a>, <code>system_complete(p)</code> has the
same semantics as <code>complete(ph, current_path())</code> if
<code>p.is_absolute() || !p.has_root_name()</code> or <code>p</code> and <code>base</code> have the same
<code>root_name()</code>.
Otherwise it acts like <code>complete(p, kinky)</code>, where <code>kinky</code>
is the current directory for the <code>p.root_name()</code> drive. This will
be the current directory of that drive the last time it was set, and thus may
be <b>residue left over from a prior program</b> run by the command
processor! Although these semantics are often useful, they are also very
error-prone.</p>
<p>See <a href="#complete_note">
<i>complete()</i> note</a> for usage suggestions. <i>-- end note</i>]</p>
</blockquote>
<pre>path <a name="temp_directory_path">temp_directory_path</a>();
path temp_directory_path(system::error_code& ec);</pre>
<blockquote>
<p><i>Returns:</i> A directory path suitable for temporary files under the
conventions of the operating system. The specifics of how this path is
determined are implementation defined. An error shall be reported if<code> !exists(p)
|| !is_directory(p)</code>, where <code>p</code> is the path to be returned.</p>
<p><i>POSIX:</i> The path supplied by the first environment variable found in the
list TMPDIR, TMP, TEMP, TEMPDIR. If none of these are found, <code>"/tmp"</code>.</p>
<p><i>Windows:</i> The path reported by the <i>Windows</i> <code>GetTempPath</code> API function.</p>
<p><i>Throws:</i> As specified in <a href="#Error-reporting">
Error reporting</a>.</p>
<p>[<i>Note: </i>The <code>temp_directory_path()</code> name was chosen to emphasize that the return is a
path, not just a single directory name. <i>-- end note</i>]</p>
</blockquote>
<pre>path <a name="unique_path">unique_path</a>(const path& model="%%%%-%%%%-%%%%-%%%%");
path unique_path(const path& model, system::error_code& ec);</pre>
<blockquote>
<p>The <code>unique_path</code> function generates a path name suitable for
creating temporary files, including directories. The name is based
on a model that uses the percent sign character to specify replacement by a
random hexadecimal digit. [<i>Note:</i> The more bits of randomness in the
generated path name, the less likelihood of prior existence or being guessed.
Each replacement hexadecimal digit in the model adds four bits of randomness.
The default model thus provides 64 bits of randomness. This is sufficient for
most applications. <i>--end note</i>]</p>
<p><i>Returns:</i> A path identical to <code>model</code>, except that each
occurrence of a percent sign character is replaced by a random hexadecimal
digit character in the range 0-9, a-f.</p>
<p><i>Throws:</i> As specified in
<a href="#Error-reporting">
Error reporting</a>.</p>
<p><i>Remarks:</i> Implementations are encouraged to obtain the required
randomness via a
<a href="http://en.wikipedia.org/wiki/Cryptographically_secure_pseudorandom_number_generator">
cryptographically secure pseudo-random number generator</a>, such as one
provided by the operating system. [<i>Note</i>: Such generators may block
until sufficient entropy develops. <i>--end note</i>]</p>
</blockquote>
$snippet wording_suffix "$SNIPPET_FILE;"
<h2><a name="Path-decomposition-table">Path decomposition table</a></h2>
<p>The table is generated by a program compiled with the Boost implementation.</p>
<p>Shaded entries indicate cases where <i>POSIX</i> and <i>Windows</i>
implementations yield different results. The top value is the
<i>POSIX</i> result and the bottom value is the <i>Windows</i> result. <br>
<table border="1" cellspacing="0" cellpadding="5">
<p>
<tr><td><b>Constructor<br>argument</b></td>
<td><b>Iteration<br>over<br>Elements</b></td>
<td><b><code>string()</code></b></td>
<td><b><code>generic_<br>string()</code></b></td>
<td><b><code>root_<br>path()</code></b></td>
<td><b><code>root_<br>name()</code></b></td>
<td><b><code>root_<br>directory()</code></b></td>
<td><b><code>relative_<br>path()</code></b></td>
<td><b><code>parent_<br>path()</code></b></td>
<td><b><code>filename()</code></b></td>
</tr>
<tr>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
</tr>
<tr>
<td><code>.</code></td>
<td><code>.</code></td>
<td><code>.</code></td>
<td><code>.</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>.</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>..</code></td>
<td><code>..</code></td>
<td><code>..</code></td>
<td><code>..</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>..</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>..</code></td>
</tr>
<tr>
<td><code>foo</code></td>
<td><code>foo</code></td>
<td><code>foo</code></td>
<td><code>foo</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo</code></td>
</tr>
<tr>
<td><code>/</code></td>
<td><code>/</code></td>
<td><code>/</code></td>
<td><code>/</code></td>
<td><code>/</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>/</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>/</code></td>
</tr>
<tr>
<td><code>/foo</code></td>
<td><code>/,foo</code></td>
<td><code>/foo</code></td>
<td><code>/foo</code></td>
<td><code>/</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>/</code></td>
<td><code>foo</code></td>
<td><code>/</code></td>
<td><code>foo</code></td>
</tr>
<tr>
<td><code>foo/</code></td>
<td><code>foo,.</code></td>
<td><code>foo/</code></td>
<td><code>foo/</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo/</code></td>
<td><code>foo</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>/foo/</code></td>
<td><code>/,foo,.</code></td>
<td><code>/foo/</code></td>
<td><code>/foo/</code></td>
<td><code>/</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>/</code></td>
<td><code>foo/</code></td>
<td><code>/foo</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>foo/bar</code></td>
<td><code>foo,bar</code></td>
<td><code>foo/bar</code></td>
<td><code>foo/bar</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo/bar</code></td>
<td><code>foo</code></td>
<td><code>bar</code></td>
</tr>
<tr>
<td><code>/foo/bar</code></td>
<td><code>/,foo,bar</code></td>
<td><code>/foo/bar</code></td>
<td><code>/foo/bar</code></td>
<td><code>/</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>/</code></td>
<td><code>foo/bar</code></td>
<td><code>/foo</code></td>
<td><code>bar</code></td>
</tr>
<tr>
<td><code>//net</code></td>
<td><code>//net</code></td>
<td><code>//net</code></td>
<td><code>//net</code></td>
<td><code>//net</code></td>
<td><code>//net</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>//net</code></td>
</tr>
<tr>
<td><code>//net/foo</code></td>
<td><code>//net,/,foo</code></td>
<td><code>//net/foo</code></td>
<td><code>//net/foo</code></td>
<td><code>//net/</code></td>
<td><code>//net</code></td>
<td><code>/</code></td>
<td><code>foo</code></td>
<td><code>//net/</code></td>
<td><code>foo</code></td>
</tr>
<tr>
<td><code>///foo///</code></td>
<td><code>/,foo,.</code></td>
<td><code>///foo///</code></td>
<td><code>///foo///</code></td>
<td><code>/</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>/</code></td>
<td><code>foo///</code></td>
<td><code>///foo</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>///foo///bar</code></td>
<td><code>/,foo,bar</code></td>
<td><code>///foo///bar</code></td>
<td><code>///foo///bar</code></td>
<td><code>/</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>/</code></td>
<td><code>foo///bar</code></td>
<td><code>///foo</code></td>
<td><code>bar</code></td>
</tr>
<tr>
<td><code>/.</code></td>
<td><code>/,.</code></td>
<td><code>/.</code></td>
<td><code>/.</code></td>
<td><code>/</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>/</code></td>
<td><code>.</code></td>
<td><code>/</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>./</code></td>
<td><code>.,.</code></td>
<td><code>./</code></td>
<td><code>./</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>./</code></td>
<td><code>.</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>/..</code></td>
<td><code>/,..</code></td>
<td><code>/..</code></td>
<td><code>/..</code></td>
<td><code>/</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>/</code></td>
<td><code>..</code></td>
<td><code>/</code></td>
<td><code>..</code></td>
</tr>
<tr>
<td><code>../</code></td>
<td><code>..,.</code></td>
<td><code>../</code></td>
<td><code>../</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>../</code></td>
<td><code>..</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>foo/.</code></td>
<td><code>foo,.</code></td>
<td><code>foo/.</code></td>
<td><code>foo/.</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo/.</code></td>
<td><code>foo</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>foo/..</code></td>
<td><code>foo,..</code></td>
<td><code>foo/..</code></td>
<td><code>foo/..</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo/..</code></td>
<td><code>foo</code></td>
<td><code>..</code></td>
</tr>
<tr>
<td><code>foo/./</code></td>
<td><code>foo,.,.</code></td>
<td><code>foo/./</code></td>
<td><code>foo/./</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo/./</code></td>
<td><code>foo/.</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>foo/./bar</code></td>
<td><code>foo,.,bar</code></td>
<td><code>foo/./bar</code></td>
<td><code>foo/./bar</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo/./bar</code></td>
<td><code>foo/.</code></td>
<td><code>bar</code></td>
</tr>
<tr>
<td><code>foo/..</code></td>
<td><code>foo,..</code></td>
<td><code>foo/..</code></td>
<td><code>foo/..</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo/..</code></td>
<td><code>foo</code></td>
<td><code>..</code></td>
</tr>
<tr>
<td><code>foo/../</code></td>
<td><code>foo,..,.</code></td>
<td><code>foo/../</code></td>
<td><code>foo/../</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo/../</code></td>
<td><code>foo/..</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>foo/../bar</code></td>
<td><code>foo,..,bar</code></td>
<td><code>foo/../bar</code></td>
<td><code>foo/../bar</code></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>foo/../bar</code></td>
<td><code>foo/..</code></td>
<td><code>bar</code></td>
</tr>
<tr>
<td><code>c:</code></td>
<td><code>c:</code></td>
<td><code>c:</code></td>
<td><code>c:</code></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><font size="-1"><i>empty</i></font></td>
<td><span style="background-color: #CCFFCC"><code>c:</code><br><font size="-1"><i>empty</i></font></span></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>c:</code></td>
</tr>
<tr>
<td><code>c:/</code></td>
<td><span style="background-color: #CCFFCC"><code>c:,.</code><br><code>c:,/</code></span></td>
<td><code>c:/</code></td>
<td><code>c:/</code></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:/</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>/</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:/</code><br><font size="-1"><i>empty</i></font></span></td>
<td><code>c:</code></td>
<td><span style="background-color: #CCFFCC"><code>.</code><br><code>/</code></span></td>
</tr>
<tr>
<td><code>c:foo</code></td>
<td><span style="background-color: #CCFFCC"><code>c:foo</code><br><code>c:,foo</code></span></td>
<td><code>c:foo</code></td>
<td><code>c:foo</code></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><font size="-1"><i>empty</i></font></td>
<td><span style="background-color: #CCFFCC"><code>c:foo</code><br><code>foo</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:foo</code><br><code>foo</code></span></td>
</tr>
<tr>
<td><code>c:/foo</code></td>
<td><span style="background-color: #CCFFCC"><code>c:,foo</code><br><code>c:,/,foo</code></span></td>
<td><code>c:/foo</code></td>
<td><code>c:/foo</code></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:/</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>/</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:/foo</code><br><code>foo</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:</code><br><code>c:/</code></span></td>
<td><code>foo</code></td>
</tr>
<tr>
<td><code>c:foo/</code></td>
<td><span style="background-color: #CCFFCC"><code>c:foo,.</code><br><code>c:,foo,.</code></span></td>
<td><code>c:foo/</code></td>
<td><code>c:foo/</code></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><font size="-1"><i>empty</i></font></td>
<td><span style="background-color: #CCFFCC"><code>c:foo/</code><br><code>foo/</code></span></td>
<td><code>c:foo</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>c:/foo/</code></td>
<td><span style="background-color: #CCFFCC"><code>c:,foo,.</code><br><code>c:,/,foo,.</code></span></td>
<td><code>c:/foo/</code></td>
<td><code>c:/foo/</code></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:/</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>/</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:/foo/</code><br><code>foo/</code></span></td>
<td><code>c:/foo</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>c:/foo/bar</code></td>
<td><span style="background-color: #CCFFCC"><code>c:,foo,bar</code><br><code>c:,/,foo,bar</code></span></td>
<td><code>c:/foo/bar</code></td>
<td><code>c:/foo/bar</code></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:/</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>/</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:/foo/bar</code><br><code>foo/bar</code></span></td>
<td><code>c:/foo</code></td>
<td><code>bar</code></td>
</tr>
<tr>
<td><code>prn:</code></td>
<td><code>prn:</code></td>
<td><code>prn:</code></td>
<td><code>prn:</code></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>prn:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>prn:</code></span></td>
<td><font size="-1"><i>empty</i></font></td>
<td><span style="background-color: #CCFFCC"><code>prn:</code><br><font size="-1"><i>empty</i></font></span></td>
<td><font size="-1"><i>empty</i></font></td>
<td><code>prn:</code></td>
</tr>
<tr>
<td><code>c:\</code></td>
<td><span style="background-color: #CCFFCC"><code>c:\</code><br><code>c:,/</code></span></td>
<td><code>c:\</code></td>
<td><span style="background-color: #CCFFCC"><code>c:\</code><br><code>c:/</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:\</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>\</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:\</code><br><font size="-1"><i>empty</i></font></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:\</code><br><code>\</code></span></td>
</tr>
<tr>
<td><code>c:foo</code></td>
<td><span style="background-color: #CCFFCC"><code>c:foo</code><br><code>c:,foo</code></span></td>
<td><code>c:foo</code></td>
<td><code>c:foo</code></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><font size="-1"><i>empty</i></font></td>
<td><span style="background-color: #CCFFCC"><code>c:foo</code><br><code>foo</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:foo</code><br><code>foo</code></span></td>
</tr>
<tr>
<td><code>c:\foo</code></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo</code><br><code>c:,/,foo</code></span></td>
<td><code>c:\foo</code></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo</code><br><code>c:/foo</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:\</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>\</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo</code><br><code>foo</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:\</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo</code><br><code>foo</code></span></td>
</tr>
<tr>
<td><code>c:foo\</code></td>
<td><span style="background-color: #CCFFCC"><code>c:foo\</code><br><code>c:,foo,.</code></span></td>
<td><code>c:foo\</code></td>
<td><span style="background-color: #CCFFCC"><code>c:foo\</code><br><code>c:foo/</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><font size="-1"><i>empty</i></font></td>
<td><span style="background-color: #CCFFCC"><code>c:foo\</code><br><code>foo\</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:foo</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:foo\</code><br><code>.</code></span></td>
</tr>
<tr>
<td><code>c:\foo\</code></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo\</code><br><code>c:,/,foo,.</code></span></td>
<td><code>c:\foo\</code></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo\</code><br><code>c:/foo/</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:\</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>\</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo\</code><br><code>foo\</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:\foo</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo\</code><br><code>.</code></span></td>
</tr>
<tr>
<td><code>c:\foo/</code></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo,.</code><br><code>c:,/,foo,.</code></span></td>
<td><code>c:\foo/</code></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo/</code><br><code>c:/foo/</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:\</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>\</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:\foo/</code><br><code>foo/</code></span></td>
<td><code>c:\foo</code></td>
<td><code>.</code></td>
</tr>
<tr>
<td><code>c:/foo\bar</code></td>
<td><span style="background-color: #CCFFCC"><code>c:,foo\bar</code><br><code>c:,/,foo,bar</code></span></td>
<td><code>c:/foo\bar</code></td>
<td><span style="background-color: #CCFFCC"><code>c:/foo\bar</code><br><code>c:/foo/bar</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:/</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>c:</code></span></td>
<td><span style="background-color: #CCFFCC"><font size="-1"><i>empty</i></font><br><code>/</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:/foo\bar</code><br><code>foo\bar</code></span></td>
<td><span style="background-color: #CCFFCC"><code>c:</code><br><code>c:/foo</code></span></td>
<td><span style="background-color: #CCFFCC"><code>foo\bar</code><br><code>bar</code></span></td>
</tr>
</table>
<h2><a name="long-path-warning"></a>Warning: Long paths on Windows and the
extended-length <b>\\?\ </b>prefix</h2>
<p>The Microsoft Windows "Maximum Path Length Limitation" specifies:</p>
<blockquote>
<p>In the Windows API (with some exceptions ...), the maximum length for a path
is MAX_PATH, which is defined as 260 characters.</p>
<p>The Windows API has many functions that also have Unicode versions to permit
an extended-length path for a maximum total path length of 32,767 characters.
... To specify an extended-length path, use the <b>"\\?\" prefix</b>. For
example, "\\?\D:\<em>very long path</em>".
<i>[C++ string literals require backslashes be doubled, of course.]</i></p>
</blockquote>
<p>Because most Boost.Filesystem operational functions just pass the contents of
a class path object to the Windows API, they do work with the extended-length
prefixes. But some won't work, because to the limitations imposed by Windows.
Read the following cautions carefully!</p>
<h3>Cautions for paths with extended-length prefixes</h3>
<ul>
<li>Individual components of a path are still are limited to whatever is
supported for the particular filesystem, commonly 255 characters.</li>
<li>Only backslashes only are acceptable as directory separators. Slashes are
not treated as separators.</li>
<li>All paths must be absolute - relative paths are not allowed.</li>
<li>Once an absolute path grows beyond 260 characters, it is essentially
poisoned and all operations must use extended-length prefixes. So even a
simple operation like <code>create_directory("a")</code> will fail if the
absolute path of the resulting directory would exceed 260 characters.</li>
<li>Certain Boost.Filesystem functions that decompose their argument path and
then work on individual relative directories or files will not work properly
with extended-length prefix paths.</li>
</ul>
<h2><a name="Acknowledgements">Acknowledgements</a></h2>
<p>This Filesystem Library is dedicated to my wife, Sonda, who provided the
support necessary to see both a trial implementation and the proposal itself
through to completion. She gave me the strength to continue after a difficult
year of cancer treatment in the middle of it all.</p>
<p>Many people contributed technical comments, ideas, and suggestions to the
Boost Filesystem Library. See
<a href="http://www.boost.org/libs/filesystem/doc/index.htm#Acknowledgements">
http://www.boost.org/libs/filesystem/doc/index.htm#Acknowledgements</a>.</p>
<p>Dietmar Kuehl contributed the original Boost Filesystem Library directory_iterator design. Peter Dimov, Walter Landry, Rob Stewart, and Thomas
Witt were particularly helpful in refining the library.</p>
<p>The create_directories, extension, basename, and replace_extension functions
were developed by Vladimir Prus. The temp_directory_path function was
contributed by Jeff Flinn. David Svoboda suggested the canonical function and
provided psuedo-code.</p>
<p>Howard Hinnant and John Maddock reviewed a draft of the version 2 proposal, and
identified a number of mistakes or weaknesses, resulting in a more polished
final document.</p>
<p>Peter Dimov suggested a single class path, with member templates to adapt to
multiple string types. His idea became the basis for the version 3 path design.</p>
<h2><a name="References">References</a></h2>
<table border="0" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%">
<tr>
<td width="16%" valign="top">[<a name="ISO_POSIX">ISO-POSIX</a>]</td>
<td width="84%">ISO/IEC 9945:2003, IEEE Std 1003.1-2001, and The Open Group
Base Specifications, Issue 6. Also known as The Single Unix<font face="Times New Roman">®
Specification, Version 3. Available from each of the organizations involved
in its creation. For example, read online or download from
<a href="http://www.unix.org/single_unix_specification/">
www.unix.org/single_unix_specification/</a>.</font> The ISO JTC1/SC22/WG15 -
POSIX homepage is <a href="http://www.open-std.org/jtc1/sc22/WG15/">
www.open-std.org/jtc1/sc22/WG15/</a></td>
</tr>
<tr>
<td width="16%" valign="top">[Abrahams]</td>
<td width="84%">Dave Abrahams, Error and Exception Handling,
<a href="http://www.boost.org/more/error_handling.html">
www.boost.org/more/error_handling.html</a></td>
</tr>
</table>
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