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<font size="7">Filesystem Library</font>
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<h1>Reference Documentation</h1>
<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="26%" valign="top"><a href="#Introduction">Introduction</a><br>
<a href="#Definitions">Definitions</a><br>
<a href="#Requirements">Requirements</a><br>
<a href="#Requirements-on-programs">Requirements on programs</a><br>
<a href="#Requirements-on-implementations">Requirementson implementations</a><br>
<a href="#Header-filesystem-synopsis">
Header <filesystem> synopsis</a><br>
<a href="#Path-traits">Path traits</a><br>
<a href="#Class-template-basic_path">
Class template basic_path</a><br>
<a href="#Pathname-formats">Pathname formats</a><br>
<a href="#Pathname-grammar">Pathname grammar</a><br>
<a href="#Filename-conversion">Filename conversion</a><br>
<a href="#basic_path-requirements">Requirements</a> </td>
<td width="35%" valign="top"> Class template basic_path (continued)<br>
<a href="#basic_path-requirements">basic_path constructors</a><br>
<a href="#basic_path-assignments">basic_path assignments</a><br>
<a href="#basic_path-modifiers">basic_path modifiers</a><br>
<a href="#basic_path-inserter-extractor">basic_path operators</a><br>
<a href="#basic_path-observers">basic_path observers</a><br>
<a href="#basic_path-iterators">basic_path iterators</a><br>
<a href="#basic_path-non-member-functions">basic_path non-member functions</a><br>
<a href="#basic_path-inserter-extractor">basic_path inserter and extractor</a><span style="background-color: #FFFFFF"><br>
</span>
<a href="#Class-template-basic_filesystem_error">Class template
basic_filesystem_error</a><br>
<a href="#basic_filesystem_error-constructors">basic_filesystem_error
constructors</a><br>
<a href="#basic_filesystem_error-observers">basic_filesystem_error observers</a><br>
<a href="#Class-template-basic_directory_entry">Class template
basic_directory_entry</a><br>
<a href="#basic_directory_entry-constructors">basic_directory_entry constructors</a><br>
<a href="#basic_directory_entry-modifiers">basic_directory_entry modifiers</a><br>
<a href="#basic_directory_entry-observers">basic_directory_entry observers</a><br>
<a href="#basic_directory_entry-comparisons">basic_directory_entry comparisons</a></td>
<td width="89%" valign="top">Filesystem library chapter (continued)<br>
<a href="#Class-template-basic_directory_iterator">Class template
basic_directory_iterator</a><br>
<a href="#basic_directory_iterator-constructors">basic_directory_iterator
constructors</a><br>
<a href="#Class-template-basic_recursive_directory_iterator">Class template
basic_recursive_directory_iterator</a><br>
<a href="#file_status">Class
file_status</a><br>
<a href="#Non-member-functions">
Non-member operational functions</a><br>
<a href="#Status-functions">Status functions</a><br>
<a href="#Predicate-functions">Predicate functions</a><br>
<a href="#Attribute-functions">Attribute functions</a><br>
<a href="#Operations-functions">Other operations functions</a><br>
<a href="#Convenience-functions">Convenience functions</a><br>
<a href="#header-fstream">Additions
to header <fstream></a><br>
<a href="#Suggestions-for-fstream">Suggestions for <code><fstream></code></a><code><br>
</code>
<a href="#Suggestions-for-fstream"> implementations</a><br>
<a href="#Path-decomposition-table">Path decomposition table</a><br>
<a href="#Acknowledgements">Acknowledgements</a><br>
<a href="#References">References</a><br>
</td>
</tr>
</table>
<p><i>Some functions have been renamed or deprecated since earlier releases of
the library. See <a href="index.htm#Deprecated-names">Deprecated names and
features</a>.</i></p>
<h2><a name="Introduction">Introduction</a></h2>
<p>Some library behavior is 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>basic_filesystem_error</code> exception, a special
return value, or some other manner. <i>--end note</i>]</p>
</blockquote>
<p>Specific operating systems such as <i>OpenMVS</i>,
<i>UNIX</i>, and <i>Windows</i> are mentioned only for purposes of illustration or to
give guidance to implementors. No slight to other operating systems is implied
or intended.</p>
<p>The <i>Effects</i> and <i>Postconditions</i> of functions described in this
reference
may not be achieved in
the presence of <a href="#Race-condition">race conditions</a>. No diagnostic is required.</p>
<p>If the possibility of race conditions makes it unreliable for a program to
test for a precondition before calling a function described in this clause, <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>
<h3><a name="Definitions">Definitions</a></h3>
<p>The following definitions apply throughout this reference documentation:</p>
<p><i><a name="File">File</a>: </i>An object that can be written to, or read from, or both. A file
has certain attributes, including type. File types include regular file,
symbolic link, and directory. Other types of files may be supported by the
implementation.</p>
<p><i><a name="File-system">File system</a>:</i> A collection of files and certain of their attributes.</p>
<p><i><a name="Filename">Filename</a>:</i> The name of a file. The format is as
specified by the <i>POSIX
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap03.html#tag_03_169">
Filename</a></i> base definition.</p>
<p><i><a name="Path">Path</a>:</i> A sequence of elements which identify
a location within a filesystem. The elements are the <i>root-name</i>, <i>
root-directory</i>, and each successive <i>filename</i>. See
<a href="#Pathname-grammar">Pathname grammar</a>.</p>
<p><i><a name="Pathname">Pathname</a>: </i>A character string that represents a
path.</p>
<p><i><a name="Link">Link</a>: </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><i><a name="Hard-link">Hard link</a>:</i> 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">Symbolic link</a>: </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><i><a name="Slash">Slash</a>:</i> The character <tt>'/'</tt>, also known as
solidus.</p>
<p><i><a name="Dot">Dot</a>:</i> The character '.', also known as period.</p>
<p><i><a name="Race-condition">Race condition</a>:</i> The condition that occurs
when multiple threads, processes, or computers interleave access and
modification of
the same object within a file system.</p>
<h3><a name="Requirements">Requirements</a></h3>
<h4><a name="Requirements-on-programs">Requirements on programs</a></h4>
<p>The arguments for template parameters named <code>Path</code>, <code>Path1</code>,
or <code>Path2</code> described in this clause shall be of type <code>basic_path</code>,
or a class derived from <code>basic_path</code>, unless otherwise
specified.</p>
<h4><a name="Requirements-on-implementations">Requirements on implementations</a></h4>
<p>Some function templates described in this clause have a template parameter
named <code>Path</code>, <code>Path1</code>, or <code>Path2</code>. When called
with a function argument <code>s</code> of type <code>char*</code> or <code>
std::string</code>, the implementation shall treat the argument as if it were
coded <code>path(s)</code>. When called with a function argument <code>s</code>
of type <code>wchar_t*</code> or <code>std::wstring</code>, the implementation
shall treat the argument as if it were coded <code>wpath(s)</code>. For
functions with two arguments, implementations shall not supply this treatment
when <code>Path1</code> and <code>Path2</code> are different types.</p>
<blockquote>
<p>[<i>Note:</i> This "do-the-right-thing" rule allows users to write <code>exists("foo")</code>,
taking advantage of class <code>basic_path</code>'s string conversion
constructor, rather
than the lengthier and more error prone <code>exists(path("foo"))</code>. This
is particularly important for the simple, script-like, programs which are an
important use case for the library. Calling two argument functions with
different types is a very rare usage, and may well be a coding error, so
automatic conversion is not supported for such cases.</p>
<p>The implementation technique is unspecified. One possible implementation
technique, using
<code>exists()</code> as an example, is:</p>
<blockquote>
<pre>template <class Path>
typename boost::enable_if<is_basic_path<Path>,bool>::type exists(const Path& p);
inline bool exists(const path& p) { return exists<path>(p); }
inline bool exists(const wpath& p) { return exists<wpath>(p); }</pre>
</blockquote>
<p> The <code>enable_if</code> will fail for a C string or <code>
std::basic_string</code> argument, which will then be automatically converted
to a <code>basic_path</code> object via the appropriate <code>basic_path</code> conversion
constructor. <i>-- end note</i>]</p>
<p><span style="background-color: #E0E0E0"><i>The two overloads are not given
in the normative text because:</i></span></p>
<ul>
<li><span style="background-color: #E0E0E0"><i>Better techniques for
achieving the desired affect may be developed, perhaps enabled by core
language changes like Concepts.</i></span></li>
<li><span style="background-color: #E0E0E0"><i>Implementations may prefer
techniques that work with legacy compilers that do not support enable_if.</i></span></li>
<li><span style="background-color: #E0E0E0"><i>Spelling out the overloads
makes the text longer and harder to read without adding much benefit.</i></span></li>
<li><span style="background-color: #E0E0E0"><i>More overloads will probably
be needed for char16_t and char32_t (or whatever they end up being called),
making it even less attractive to actually spell out each one. </i></span>
</li>
</ul>
</blockquote>
<p>Implementations of functions described in this clause are permitted to call the applications
program interface (API) provided by the operating system. If such an operating
system API call results in an error, implementations
shall report the error by throwing exception <code>basic_filesystem_error</code>,
unless otherwise specified.</p>
<blockquote>
<p>[<i>Note: </i>Such exceptions and the conditions that cause them to be thrown
are not explicitly described in each <i>Throws</i> element within this clause.
Because hardware failures, network failures, race conditions, and a plethora of
other errors occur frequently in file system operations, users should be aware
that <span style="background-color: #FFFFFF">unless otherwise specified</span> any file system operation, not matter how apparently innocuous, may throw
an exception. <i>-- end note</i>]</p>
</blockquote>
<p><span style="background-color: #FFFFFF">Functions commonly used in contexts
where errors are not exceptional have overloads taking an additional argument of
type </span><code><span style="background-color: #FFFFFF">error_code& ec</span></code><span style="background-color: #FFFFFF">. Such overloaded functions shall not throw exceptions. If an error occurs,
<code>ec</code> shall be set to the
error code reported by the operating system, otherwise <code>ec</code> shall be set to 0. If
an overload without an argument of type </span><code>
<span style="background-color: #FFFFFF">error_code& ec</span></code><span style="background-color: #FFFFFF"> returns void, the other overload (with an argument of type </span><code>
<span style="background-color: #FFFFFF">error_code& ec</span></code><span style="background-color: #FFFFFF">) returns an <code>
error_code</code> with the value of ec.</span></p>
<h3><a name="Header-filesystem-synopsis">Header <code><boost/filesystem></code> synopsis</a></h3>
<pre> namespace boost
{
namespace filesystem
{
template <class String, class Traits> class <a href="#Class-template-basic_path">basic_path</a>;
template<class String, class Traits>
void swap(basic_path<String, Traits> & lhs, basic_path<String, Traits> & rhs);
template<class String, class Traits> bool operator<(<i>a</i> a, <i>b</i> b);
template<class String, class Traits> bool operator==(<i>a</i> a, <i>b</i> b);
template<class String, class Traits> bool operator!=(<i>a</i> a, <i>b</i> b);
template<class String, class Traits> bool operator>(<i>a</i> a, <i>b</i> b);
template<class String, class Traits> bool operator<=(<i>a</i> a, <i>b</i> b);
template<class String, class Traits> bool operator>=(<i>a</i> a, <i>b</i> b);
template<class String, class Traits> bool operator/(<i>a</i> a, <i>b</i> b);
template<class Path>
basic_ostream<typename Path::string_type::value_type, typename Path::string_type::traits_type> &
operator<<(basic_ostream<typename Path::string_type::value_type, typename Path::string_type::traits_type>& os, const Path & ph);
template<class Path>
basic_istream<typename Path::string_type::value_type, typename Path::string_type::traits_type> &
operator>>(basic_istream<typename Path::string_type::value_type, typename Path::string_type::traits_type>& is, Path & ph);
struct path_traits;
struct wpath_traits;
typedef basic_path<std::string, path_traits> path;
typedef basic_path<std::wstring, wpath_traits> wpath;
template<class Path> struct is_basic_path;
template<class Path> struct slash { static const char value = '/'; };
template<class Path> struct dot { static const char value = '.'; };
<span style="background-color: #FFFFFF"> template<class Path> struct colon { static const char value = ':'; };</span><span style="background-color: #FFFF00">
</span>
<span style="background-color: #FFFFFF">class filesystem_error;</span><span style="background-color: #FFFF00">
</span>
template <class Path> class <a href="#Class-template-basic_filesystem_error">basic_filesystem_error</a>;
typedef basic_filesystem_error<path> filesystem_error;
typedef basic_filesystem_error<wpath> wfilesystem_error;
<span style="background-color: #FFFFFF">template <class Path> class <a href="#Class-template-basic_directory_entry">basic_directory_entry</a>;
typedef basic_directory_entry<path> directory_entry;
typedef basic_directory_entry<wpath> wdirectory_entry;
</span>
template <class Path> class <a href="#Class-template-basic_directory_iterator">basic_directory_iterator</a>;
typedef basic_directory_iterator<path> directory_iterator;
typedef basic_directory_iterator<wpath> wdirectory_iterator;
template <class Path> class <a href="#Class-template-basic_recursive_directory_iterator">basic_recursive_directory_iterator</a>;
typedef basic_recursive_directory_iterator<path> <a name="recursive_directory_iterator">recursive_directory_iterator</a>;
typedef basic_recursive_directory_iterator<wpath> wrecursive_directory_iterator;
enum file_type { status_unknown, file_not_found, regular_file, directory_file,
symlink_file, block_file, character_file, fifo_file, socket_file,
type_unknown
};
class <a href="#file_status">file_status</a>;
<span style="background-color: #FFFFFF">struct space_info // returned by </span><a href="#space" style="text-decoration: none"><span style="background-color: #FFFFFF">space</span></a><span style="background-color: #FFFFFF"> function
{
uintmax_t capacity;
uintmax_t free;
uintmax_t available;
};
</span>
// <a href="#Status-functions">status functions</a>
template <class Path> file_status status(const Path& p);
template <class Path> file_status status(const Path& p, error_code& ec);
template <class Path> file_status symlink_status(const Path& p);
template <class Path> file_status symlink_status(const Path& p, error_code& ec);
// <a href="#Predicate-functions">predicate functions</a>
bool status_known( file_status s );
bool exists( file_status s );
bool is_regular_file( file_status s );
bool is_directory( file_status s );
bool is_symlink( file_status s );
bool is_other( file_status s );
template <class Path> bool exists(const Path& p);
template <class Path> bool is_directory(const Path& p);
template <class Path> bool is_regular_file(const Path& p);
template <class Path> bool is_other(const Path& p);
template <class Path> bool is_symlink(const Path& p);
template <class Path> bool is_empty(const Path& p);
template <class Path1, class Path2>
bool equivalent(const Path1& p1, const Path2& p2);
// <a href="#Attribute-functions">attribute functions</a>
template <class Path> Path current_path();
template <class Path> void current_path(const Path& p);
template <class Path> const Path& initial_path();
template <class Path> <span style="background-color: #FFFFFF; ">uintmax_t</span> file_size(const Path& p);
<span style="background-color: #FFFFFF"> template <class Path> space_info space(const Path& p);</span><span style="background-color: #FFFF00">
</span> template <class Path> std::time_t last_write_time(const Path& p);
template <class Path>
void last_write_time(const Path& p, const std::time_t new_time);
// <a href="#Operations-functions">operations functions</a>
template <class Path> bool create_directory(const Path& dp);
template <class Path1, class Path2>
void create_hard_link(const Path1& old_fp, const Path2& new_fp);
<span style="background-color: #FFFFFF"> template <class Path1, class Path2>
error_code create_hard_link(const Path1& old_fp, const Path2& new_fp, error_code& ec);
template <class Path1, class Path2>
void create_symlink(const Path1& old_fp, const Path2& new_fp);
template <class Path1, class Path2>
error_code create_symlink(const Path1& old_fp, const Path2& new_fp, error_code& ec);
</span> template <class Path> bool remove(const Path& p);
template <class Path1, class Path2>
void rename(const Path1& from_p, const Path2& to_p);
BOOST_SCOPED_ENUM_START(<a name="copy_option">copy_option</a>)
{ fail_if_exists, overwrite_if_exists };
BOOST_SCOPED_ENUM_END
template <class Path1, class Path2>
void copy_file(const Path1& from_fp, const Path2& to_fp,
BOOST_SCOPED_ENUM(copy_option) option=copy_option::fail_if_exists);
template <class Path> Path system_complete(const Path& p);
template <class Path> Path complete(const Path& p, const Path& base=initial_path<Path>());
// <a href="#Convenience-functions">convenience functions</a>
template <class Path> bool create_directories(const Path& p);
template <class Path> typename Path::string_type extension(const Path& p);
template <class Path> typename Path::string_type basename(const Path& p);
template <class Path>
Path change_extension(const Path& p, const typename Path::string_type& new_extension);
} // namespace filesystem
} // namespace boost</pre>
<h3><a name="Path-traits">Path traits</a></h3>
<p>This subclause defines requirements on classes representing path behavior
traits, and defines two classes that satisfy those requirements for paths based
on <code>string</code> and <code>wstring</code>.. It also defines several path
additional path traits structure templates, and defines several specializations
of them.</p>
<p>Class template <code>basic_path</code> defined in this clause requires additional
types, values, and behavior to complete the definition of its semantics.</p>
<p>For purposes of exposition, Traits behaves as if it is a class with private
members bool m_locked, initialized false, and std::locale m_locale, initialized </p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%">
<tr>
<td width="50%" align="center" colspan="2"><b><i>
<a name="Path-Behavior-Traits-Requirements">Path Behavior Traits
Requirements</a></i></b></td>
</tr>
<tr>
<td width="38%" align="center"><b><i>Expression</i></b></td>
<td width="62%" align="center"><b><i>Requirements</i></b></td>
</tr>
<tr>
<td width="38%" valign="top"><code>Traits::external_string_type</code></td>
<td width="62%">A typedef which is a specialization of <code>basic_string</code>.
The <code>value_type</code> is a character type used by the operating system
to represent pathnames.</td>
</tr>
<tr>
<td width="38%" valign="top"><code>Traits::internal_string_type</code></td>
<td width="62%">A typedef which is a specialization of <code>basic_string</code>.
The <code>value_type</code> is a character type to be used by the program to
represent pathnames. Required be the same type as the <code>basic_path
String</code> template parameter. </td>
</tr>
<tr>
<td width="38%" valign="top"><code>Traits::to_external( p, is )</code></td>
<td width="62%"><code>is</code>, converted by the <code>m_locale</code>
<code>codecvt</code> facet to <code>external_string_type</code>.</td>
</tr>
<tr>
<td width="38%" valign="top"><code>Traits::to_internal( p, xs )</code></td>
<td width="62%"><code>xs</code>, converted by the <code>m_locale</code>
<code>codecvt</code> facet to to <code>internal_string_type</code>.</td>
</tr>
<tr>
<td width="38%" valign="top"><code>Traits::imbue(loc)</code></td>
<td width="62%"><i>Effects:</i> if <code>m_locked</code>, throw. Otherwise,
<code>m_locked = true; m_locale = loc;<br>
</code><i>Returns:</i> <code>void</code><b><br>
</b><i>Throws:</i> <code>basic_filesystem_error</code></td>
</tr>
<tr>
<td width="38%" valign="top"><code>Traits::imbue(loc, std::nothrow)</code></td>
<td width="62%"><i>Effects:</i> <code>if (!m_locked) m_locale = loc; bool
temp(m_locked); m_locked = true;<br>
</code><i>Returns:</i> <code>temp</code></td>
</tr>
</table>
<p>Type <code>is_basic_path</code> shall be a <i>UnaryTypeTrait</i> (TR1, 4.1).
The primary template shall be derived directly or indirectly from <code>
std::tr1::false_type</code>. Type <code>is_basic_path</code> shall be
specialized for <code>path</code>, <code>wpath</code>, and any
user-specialized <code>basic_path</code> types, and such specializations shall
be derived directly or indirectly from <code>std::tr1::true_type</code>.</p>
<p>Structure templates <code>slash</code>, <code>dot</code>, and <code>
<span style="background-color: #FFFFFF">colon</span></code><span style="background-color: #FFFFFF">
</span>are supplied with
values of type <code>char</code>. If a user-specialized <code>basic_path</code>
has a <code>
value_type</code> type which is not convertible from <code>char</code>, the
templates <code>slash</code> and <code>dot</code> shall be specialized to
provide <code>value</code> with type which is convertible to <code>
basic_path::value_type</code>.</p>
<h3><a name="Class-template-basic_path">Class template <code>basic_path</code></a></h3>
<p>Class template <code>basic_path</code> provides a portable mechanism for
representing <a href="#Path">paths</a> in C++ programs, using a portable generic
pathname <a href="#Pathname-grammar">grammar</a>. When portability is not a
requirement, native file system specific formats can be used. Class template
<code>basic_path</code> is concerned only with the lexical and syntactic aspects
of a path. The path does not have to exist in the operating system's file
system, and may contain names which are not even valid for the current operating
system. </p>
<blockquote>
<p>[<i>Note: </i>If the library's functions trafficked only in C++<i> </i>or
C-style strings, they would provide only the illusion of portability since
while the syntax of function calls would be portable, the semantics of the
strings they operate on would not be portable. <i>-- end note</i>]</p>
</blockquote>
<pre> namespace boost
{
namespace filesystem
{
template <class String, class Traits> class basic_path
{
public:
typedef basic_path<String, Traits> path_type;
typedef String string_type;
typedef typename String::value_type value_type;
typedef Traits traits_type;
typedef typename Traits::external_string_type external_string_type;
// <a href="#basic_path-constructors">constructors/destructor</a>
basic_path();
basic_path(const basic_path& p);
basic_path(const string_type& s);
basic_path(const value_type* s);
template <class InputIterator>
basic_path(InputIterator first, InputIterator last);
~basic_path();
// <a href="#basic_path-assignments">assignments</a>
basic_path& operator=(const basic_path& p);
basic_path& operator=(const string_type& s);
basic_path& operator=(const value_type* s);
template <class InputIterator>
basic_path& assign(InputIterator first, InputIterator last);
// <a href="#basic_path-modifiers">modifiers</a>
basic_path& operator/=(const basic_path& rhs);
basic_path& operator/=(const string_type& s);
basic_path& operator/=(const value_type* s);
template <class InputIterator>
basic_path& append(InputIterator first, InputIterator last);
<span style="background-color: #FFFFFF">void clear();
void swap( basic_path & rhs );</span>
basic_path& remove_filename();
basic_path& replace_extension(const string_type & new_extension = "");
// <a href="#basic_path-observers">observers</a>
const string_type string() const;
const string_type file_string() const;
const string_type directory_string() const;
const external_string_type external_file_string() const;
const external_string_type external_directory_string() const;
string_type root_name() const;
string_type root_directory() const;
basic_path root_path() const;
basic_path relative_path() const;
basic_path parent_path() const;
string_type filename() const;
string_type stem() const;
string_type extension() const;
bool empty() const;
bool is_complete() const;
bool has_root_name() const;
bool has_root_directory() const;
bool has_root_path() const;
bool has_relative_path() const;
bool has_filename() const;
bool has_parent_path() const;
// <a href="#basic_path-iterators">iterators</a>
class iterator;
typedef iterator const_iterator;
iterator begin() const;
iterator end() const;
};
} // namespace filesystem
} // namespace boost</pre>
<p>A <code>basic_path</code> object stores a possibly empty <a href="#Path">path</a>.
The internal form of the stored path is unspecified.</p>
<p><a name="pathname-resolution">Functions</a> described in this clause which access files or their attributes do so by
resolving a <code>basic_path</code> object into a particular file in a file
hierarchy. The pathname, suitably converted to the string type, format, and
encoding
required by the operating system, 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. The encoding of the resulting pathname is determined by the <code>Traits::to_external</code> conversion function.</p>
<blockquote>
<p>[<i>Note:</i> There is no guarantee that the path stored in a <code>basic_path</code>
object is valid for a particular operating system or file system. <i>-- end note</i>]</p>
</blockquote>
<p>Some functions in this clause return <code>basic_path</code> objects for
paths composed partly or wholly of pathnames obtained from the operating system.
Such pathnames are suitably converted from the actual format and string
type supplied by the operating system. The encoding of the resulting path is determined by the <code>Traits::to_internal</code> conversion function.</p>
<p>For member functions described as returning "<code>const string_type</code>" or
"<code>const external_string_type</code>", implementations are permitted to return
"<code>const string_type&</code>" or "<code>const external_string_type&</code>"
respectively.</p>
<blockquote>
<p>[<i>Note:</i> This allows implementations to avoid unnecessary copies.
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>
<h4><a name="Pathname-formats">Pathname formats</a></h4>
<p>There are two formats for string or sequence arguments that describe a
path:</p>
<ul>
<li>The portable pathname format as described in <a href="#Pathname-grammar">
Pathname grammar</a> and by the <i>POSIX</i> <i><a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap03.html#tag_03_169">Filename</a>,
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap03.html#tag_03_266">
Pathname</a> </i>and<i>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap04.html#tag_04_11">
Pathname Resolution</a></i> definitions.<blockquote>
<p>[<i>Note:</i> <span style="background-color: #FFFFFF">The <i>POSIX</i> format
is the basis for the portable format because it is already an ISO standard, is
the basis for the ubiquitous <i>URL</i> format, and is the native format or a
subset of the native format for <i>UNIX</i>-like and <i>Windows</i>-like
operating systems familiar to large numbers of programmers. </span></p>
<p>Use of the portable format does not alone guarantee
portability; filenames must also be portable.<span style="background-color: #FFFFFF">
See <a href="#Filename-conversion">Filename conversions</a>. Each operating system
follows its own rules. Use of the portable format
does not change that. </span> <i>-- end note</i>]</p>
</blockquote>
</li>
<li>A native pathname format
as defined by the operating system.<blockquote>
<p>[<i>Note:</i> If an operating system supports only the <i>POSIX</i>
pathname format, the portable format and the native format are the same. </p>
<p><span style="background-color: #FFFFFF">Identifying user-provided paths
as native format is a common need, and ensures maximum portability, even
though not strictly needed except on systems where the native format
is not implicitly recognized.</span></p>
<p><span style="background-color: #FFFFFF">Programs using hard-coding native
formats are likely to be non-portable. --</span><i><span style="background-color: #FFFFFF"> end note</span></i><span style="background-color: #FFFFFF">]</span></p>
</blockquote>
</li>
</ul>
<p><span style="background-color: #FFFFFF">All <code>basic_path</code> string or sequence arguments that describe a
path shall accept the portable pathname format, and shall accept the native
format if explicitly identified by a native format escape sequence prefix of
<code>slash slash colon</code>.</span></p>
<blockquote>
<p><span style="background-color: #FFFFFF">[<i>Note:</i> <code>slash
slash colon</code> was chosen as the escape sequence because a leading <code>
slash slash</code> is already implementation-defined by POSIX, <code>
colon</code> is prohibited in a Windows filename, and on any system a single
<code>slash</code> can be used when a filename beginning with a <code>colon</code>
is desired. These factors eliminate the chance of collision with a real
filename. --</span><i><span style="background-color: #FFFFFF"> end note</span></i><span style="background-color: #FFFFFF">]</span></p>
</blockquote>
<p><span style="background-color: #FFFFFF">Implementations are encouraged to
implicitly recognize the native pathname format if it can be lexically
identified. An implementation </span>shall document whether or
not the native pathname format is <span style="background-color: #FFFFFF">
implicitly recognized</span>.</p>
<blockquote>
<p>[<i>Example:</i></p>
<p><i>-- OpenVMS:</i> <code>"SYS1::DISK1:[JANE.TYLER.HARRY]</code>" is treated
as a native pathname with a system name, drive name, and three directory
filenames, rather than a portable pathname with one filename.</p>
<p><i>-- Windows: </i><code>"c:\\jane\\tyler\\harry"</code> is treated as a
native pathname with a drive letter, root-directory, and three filenames, rather
than a portable pathname with one filename.</p>
<p><i>-- Counter-example 1:</i> An operating system that allows slashes in
filenames and uses dot as a directory separator. Distinguishing between portable
and native format argument strings or sequences is not possible as there is no
other distinguishing syntax. The implementation does not accept native format
pathnames unless the <code>native</code> argument is present.</p>
<p><i>-- Counter-example 2:</i> An operating system that allows slashes in
filenames and uses some unusual character as a directory separator. The
implementation does accept native format pathnames without the additional <code>
native</code> argument, which only has to be used for native format arguments
containing slashes in filenames.</p>
<p><i>-- end example</i>]</p>
<p>[<i>Note:</i> This <i><a name="duck-rule">duck-rule</a></i> ("if it looks
like a duck, walks like a duck, and quacks like a duck, it must be a duck")
eliminates format confusion as a source of programmer error and support
requests. <i>-- end note</i>]</p>
</blockquote>
<p>If both the portable and native formats are accepted, implementations shall
document what characters or character sequences are used to distinguish between
portable and native formats.</p>
<blockquote>
<p>[<i>Note:</i> <i>Windows</i> implementations are encouraged to define colons
and backslashes as the characters which distinguish native from portable
formats. <i>--end note</i>]</p>
</blockquote>
<h4><a name="Pathname-grammar">Pathname grammar</a></h4>
<p>The grammar for the portable pathname format is as follows:</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>
<p><i>root-directory:<br>
slash<br>
root-directory slash<br>
implementation-defined</i></p>
<p><i>relative-path:<br>
filename<br>
relative-path
slash<br>
relative-path
slash filename</i></p>
<p><i>filename:<br>
name<br>
dot<br>
dot dot</i></p>
<p><i>slash:<br>
<code>
slash<Path>::value</code></i></p>
<p><i>dot:<br>
<code>
dot<Path>::value</code></i></p>
</blockquote>
<p>The grammar is aligned with the <i>POSIX </i> <i><a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap03.html#tag_03_169">Filename</a>,
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap03.html#tag_03_266">
Pathname</a> </i>and<i>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap04.html#tag_04_11">
Pathname Resolution</a></i> definitions. Any conflict between the grammar and <i>
POSIX</i> is unintentional. This technical report defers to <i>POSIX</i>.</p>
<blockquote>
<p><span style="background-color: #E0E0E0"><i>The form of the above wording was taken
from POSIX, which uses it in several places to defer to the C standard.</i></span></p>
<p>[<i>Note: Windows</i> implementations are encouraged to define <i>slash slash
name</i> as a permissible <i>root-name</i>. <i>POSIX</i> permits, but does not
require, implementations to do the same. <i>Windows</i> implementations are
encouraged to define an additional <i>root-directory</i> element <i>
root_directory name.</i> It is applicable only to the <i>slash slash name</i>
form of <i>root-name.</i></p>
<p> <i>Windows</i> implementations are encouraged to recognize a <i>name</i>
followed by a colon as a native format <i>root-name</i>,
and a backslash as a format element equivalent to <i>slash</i>. <i>-- end note</i>]</p>
</blockquote>
<h4><a name="Filename-conversion">Filename conversion</a></h4>
<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>
<p><span style="background-color: #E0E0E0"><i>The Boost implementation for
Windows currently does not map invalid characters. Pending feedback from the LWG,
Boost may settle on % hex hex as the preferred escape sequence. If so, should
there be normative encouragement?</i></span></p>
</blockquote>
<h4><a name="basic_path-requirements">Requirements</a></h4>
<p>The argument for the template parameter named <code>String</code> shall be a
class that includes members with the same names, types, values, and semantics as
class template <code>basic_string</code>.</p>
<p>The argument for the template parameter named <code>Traits</code> shall be a
class that satisfies the requirements specified in the
<a href="#Path-Behavior-Traits-Requirements">Path Behavior Traits Requirements</a>
table.</p>
<p>The argument for template parameters named <code>InputIterator</code> shall satisfy the
requirements of an input iterator (C++ Std, 24.1.1, Input iterators [lib.input.iterators]) and shall have a value type convertible to
<code>basic_path::value_type</code>. </p>
<p>Some function templates with a template
parameter named <code>InputIterator</code> also have non-template overloads. Implementations shall
only select the function template overload if the type named by <code>InputIterator</code>
is not <code>path_format_t</code>.</p>
<blockquote>
<p>[<i>Note:</i> This "do-the-right-thing" rule ensures that the
overload expected by the user is selected. The implementation technique is unspecified -
implementations may use
<a href="http://www.boost.org/libs/utility/enable_if.html">enable_if</a> or
other techniques to achieve the effect. <i>-- end note</i>]</p>
</blockquote>
<h4> <a name="basic_path-constructors"> <code>basic_path</code> constructors</a></h4>
<pre>basic_path();</pre>
<blockquote>
<p><i>Postconditions:</i> <code>empty()</code>.</p>
</blockquote>
<pre>basic_path(const string_type& s);
basic_path(const value_type * s);
template <class InputIterator>
basic_path(InputIterator s, InputIterator last);</pre>
<blockquote>
<p><i>Remarks:</i> The format of string <code>s</code> and sequence [<code>first</code>,<code>last</code>)
is described in <a href="#Pathname-formats">Pathname formats</a>.</p>
<p><i>Effects:</i> The path elements in string <code>s</code> or sequence [<code>first</code>,<code>last</code>)
are stored.</p>
</blockquote>
<h4> <a name="basic_path-assignments"> <code>basic_path</code> assignments</a></h4>
<pre>basic_path& operator=(const string_type& s);
basic_path& operator=(const value_type* s);
template <class InputIterator>
basic_path& assign(InputIterator first, InputIterator last);</pre>
<blockquote>
<p><i>Remarks:</i> The format of string <code>s</code> and sequence [<code>first</code>,<code>last</code>)
is described in <a href="#Pathname-formats">Pathname formats</a>.</p>
<p><i>Effects:</i> The path elements in string <code>s</code> or sequence [<code>first</code>,<code>last</code>)
are stored.</p>
<p><i>Returns: </i><code>*this</code></p>
</blockquote>
<h4> <a name="basic_path-modifiers"> <code>basic_path</code> modifiers</a></h4>
<pre>basic_path& operator/=(const basic_path& rhs);</pre>
<blockquote>
<p><i>Effects:</i> The path stored in <code>rhs</code> is appended to the
stored path.</p>
<p><i>Returns:</i> <code>*this</code></p>
</blockquote>
<pre>basic_path& operator/=(const string_type& s);
basic_path& operator/=(const value_type* s);
template <class InputIterator>
basic_path& append(InputIterator first, InputIterator last);</pre>
<blockquote>
<p><i>Remarks:</i> The format of string <code>s</code> and sequence [<code>first</code>,<code>last</code>)
is described in <a href="#Pathname-formats">Pathname formats</a>.</p>
<p><i>Effects:</i> The path elements in string <code>s</code> or sequence [<code>first</code>,<code>last</code>)
are appended to the stored path.</p>
<p><i>Returns: </i><code>*this</code></p>
</blockquote>
<pre>void clear();</pre>
<blockquote>
<p><i>Postcondition:</i> <code>this->empty()</code> is true.</p>
</blockquote>
<pre><code><span style="background-color: #FFFFFF">void swap( basic_path & rhs );</span></code></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Effects:</span></i><span style="background-color: #FFFFFF">
Swaps the contents of the two paths.</span></p>
<p><i><span style="background-color: #FFFFFF">Throws: </span></i>
<span style="background-color: #FFFFFF">nothing.</span></p>
<p><i><span style="background-color: #FFFFFF">Postcondition:</span></i><span style="background-color: #FFFFFF">
</span><code><span style="background-color: #FFFFFF">this->string()</span></code><span style="background-color: #FFFFFF">
contains the same sequence of characters that were in </span><code><span style="background-color: #FFFFFF">
rhs.string()</span></code><span style="background-color: #FFFFFF">, </span><code><span style="background-color: #FFFFFF">
rhs.string()</span></code><span style="background-color: #FFFFFF">
contains the same sequence of characters that were is </span><code>
<span style="background-color: #FFFFFF">this->string()</span></code><span style="background-color: #FFFFFF">.</span></p>
<p><i><span style="background-color: #FFFFFF">Complexity: </span></i>
<span style="background-color: #FFFFFF">constant time.</span></p>
</blockquote>
<pre>basic_path& remove_filename();</pre>
<blockquote>
<p><i>Effects:</i> If <code>has_parent_path()</code> then remove the last <i>filename</i> from the stored path. If that leaves
the stored path with one or more trailing <i>slash</i> elements not
representing <i>root-directory</i>, remove them.</p>
<p><i>Returns:</i> <code>*this</code></p>
<p>[<i>Note:</i> This function is needed to efficiently implement <code>
basic_directory_iterator</code>. It is made public to allow additional uses. <i>-- end
note</i>]</p>
</blockquote>
<pre>basic_path& replace_extension( const string_type & new_extension = "" );</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>
<h4> <a name="basic_path-observers"> <code>basic_path</code> observers</a></h4>
<blockquote>
<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.</i></span></p>
</blockquote>
<pre>const string_type string() const;</pre>
<blockquote>
<p><i>Returns:</i> The stored path, formatted according to the
<a href="#Pathname-grammar">Pathname grammar</a> rules.</p>
</blockquote>
<pre>const string_type file_string() const;</pre>
<blockquote>
<p><i>Returns:</i> The stored path, formatted according to the
operating system rules for regular file pathnames, with any
<a href="#Filename-conversion">Filename conversion</a> applied.</p>
<p>[<i>Note:</i> For some operating systems, including <i>POSIX</i> and <i>
Windows</i>, the native format for regular file pathnames and directory
pathnames is the same, so <code>file_string()</code> and <code>directory_string()</code>
return the same string. On OpenMVS, however, the expression <code>path("/cats/jane").file_string()</code>
would return the string <code>"[CATS]JANE"</code> while <code>path("/cats/jane").directory_string()</code>
would return the string <code>"[CATS.JANE]"</code>. <i>-- end note</i>]</p>
</blockquote>
<pre>const string_type directory_string() const;</pre>
<blockquote>
<p><i>Returns:</i> The stored path, formatted according to the
operating system rules for directory pathnames, with any
<a href="#Filename-conversion">Filename conversion</a> applied.</p>
</blockquote>
<pre>const external_string_type external_file_string() const;</pre>
<blockquote>
<p><i>Returns:</i> The stored path, formatted according to the
operating system rules for regular file pathnames, with any
<a href="#Filename-conversion">Filename conversion</a> applied, and encoded by the <code>Traits::to_external</code>
conversion function.</p>
</blockquote>
<pre>const external_string_type external_directory_string() const;</pre>
<blockquote>
<p><i>Returns:</i> The stored path, formatted according to the
operating system rules for directory pathnames, with any
<a href="#Filename-conversion">Filename conversion</a> applied, and encoded by the <code>Traits::to_external</code>
conversion function.</p>
</blockquote>
<pre>string_type root_name() const;</pre>
<blockquote>
<p><i>Returns:</i> <i>root-name,</i> if the stored path includes <i>
root-name</i>, otherwise <code>string_type()</code>. </p>
</blockquote>
<pre>string_type root_directory() const;</pre>
<blockquote>
<p><i>Returns:</i> <i>root-directory</i>, if the stored path includes <i>
root-directory</i>, otherwise <code>string_type()</code>.</p>
<p>If <i>root-directory</i> is composed <i>slash name</i>, <i>slash</i> is
excluded from the returned string.</p>
</blockquote>
<pre>basic_path root_path() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>root_name() / root_directory()</code></p>
</blockquote>
<pre>basic_path relative_path() const;</pre>
<blockquote>
<p><i>Returns:</i> A <code>basic_path</code> composed from the the stored path, if any, beginning
with the first <i>filename</i> after <i>root-path</i>.
Otherwise, an empty <code>basic_path</code>.</p>
</blockquote>
<pre>string_type filename() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>empty() ? string_type() : *--end()</code></p>
</blockquote>
<pre>basic_path parent_path() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>(string().empty() || begin() == --end()) ? path_type("") :
<i>br</i></code>, where <code><i>br</i></code> is constructed as if by
starting with an empty <code>basic_path</code> and successively applying <code>
operator/=</code> for each element in the range <code>begin()</code>, <code>
--end()</code>.</p>
</blockquote>
<pre>string_type stem(const Path & p) const;</pre>
<blockquote>
<p><i>Returns:</i> if <code>p.filename()</code> contains a <i>dot</i>, returns
the substring of <code>p.filename()</code> starting at its beginning and
ending at the last <i>dot</i> (the <i>dot</i> is not included). Otherwise,
returns <code>
p.filename()</code>.</p>
</blockquote>
<pre>string_type extension(const Path & p) const;</pre>
<blockquote>
<p><i>Returns:</i> if <code>p.filename()</code> contains a <i>dot</i>, returns
the substring of <code>p.filename()</code> starting at the rightmost <i>dot</i>
and ending at the string's end. Otherwise, returns an empty string. </p>
<p>[<i>Note:<b> </b></i>The <i>dot</i> is included in the return value so that
it is possible to distinguish between no extension and an empty extension. </p>
<p>Implementations are permitted but not required to define additional
behavior for file systems which append additional elements to extensions, such
as alternate data stream or partitioned dataset names. <i>-- end note</i>]</p>
</blockquote>
<pre>bool empty() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>string().empty()</code>.</p>
</blockquote>
<pre>bool is_complete() const;</pre>
<blockquote>
<p><span style="background-color: #FFFFFF"><i>Returns:</i> <code>true</code>,
if the elements of root_path() uniquely identify a directory, else <code>false</code>.</span></p>
</blockquote>
<pre>bool has_root_path() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!root_path().empty()</code></p>
</blockquote>
<pre>bool has_root_name() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!root_name().empty()</code></p>
</blockquote>
<pre>bool has_root_directory() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!root_directory().empty()</code></p>
</blockquote>
<pre>bool has_relative_path() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!relative_path().empty()</code></p>
</blockquote>
<pre>bool has_filename() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!filename().empty()</code></p>
</blockquote>
<pre>bool has_parent_path() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>!parent_path().empty()</code></p>
</blockquote>
<h4> <a name="basic_path-iterators"> <code>basic_path</code> iterators</a></h4>
<p> A <code>basic_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>string_type</code>.</p>
<p>Calling any non-const member function of a <code>basic_path</code> object
invalidates all iterators referring to elements of the 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>
<h4> <a name="basic_path-non-member-functions">
<span style="background-color: #FFFFFF">basic_path non-member functions</span></a></h4>
<pre><span style="background-color: #FFFFFF">template<class String, class Traits>
void swap( basic_path<String, Traits> & lhs, basic_path<String, Traits> & rhs )</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Effects: </span></i><code>
<span style="background-color: #FFFFFF">lhs.swap(
rhs )</span></code></p>
</blockquote>
<h4><span style="background-color: #FFFFFF">basic_path non-member operators</span></h4>
<p><span style="background-color: #FFFFFF">There are seven basic_path non-member operators (/,
</span> <code><span style="background-color: #FFFFFF">==</span></code><span style="background-color: #FFFFFF">,
</span> <code>
<span style="background-color: #FFFFFF">!=</span></code><span style="background-color: #FFFFFF">,
</span> <code><span style="background-color: #FFFFFF"><</span></code><span style="background-color: #FFFFFF">,
</span> <code><span style="background-color: #FFFFFF">></span></code><span style="background-color: #FFFFFF">,
</span> <code><span style="background-color: #FFFFFF"><=</span></code><span style="background-color: #FFFFFF">,
</span> <code><span style="background-color: #FFFFFF">>=</span></code><span style="background-color: #FFFFFF">),
each with five overloads. For brevity, the specifications are given in tabular
form. Each of the resulting thirty-five signatures is a template, with
template parameter list template</span><code><span style="background-color: #FFFFFF"><class
String, class Traits></span></code><span style="background-color: #FFFFFF">.
The format of such arguments is described in </span> <a href="#Pathname-formats">
<span style="background-color: #FFFFFF">Pathname formats</span></a><span style="background-color: #FFFFFF">.</span></p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%">
<tr>
<td width="100%">
<p align="center"><i><b><span style="background-color: #FFFFFF">Argument type overloads</span></b></i></td>
</tr>
<tr>
<td width="100%"><span style="background-color: #FFFFFF"><code>
basic_path<String, Traits>& a, basic_path<String, Traits>&
b</code></span></td>
</tr>
<tr>
<td width="100%"><span style="background-color: #FFFFFF"><code>const
typename basic_path<String, Traits>::string_type& a,
basic_path<String, Traits>& b</code></span></td>
</tr>
<tr>
<td width="100%"><span style="background-color: #FFFFFF"><code>const
typename basic_path<String, Traits>::string_type::value_type* a,
basic_path<String, Traits>& b</code></span></td>
</tr>
<tr>
<td width="100%"><span style="background-color: #FFFFFF"><code>const
basic_path<String, Traits>& a, typename basic_path<String, Traits>::string_type&
b</code></span></td>
</tr>
<tr>
<td width="100%"><span style="background-color: #FFFFFF"><code>const
basic_path<String, Traits>& a, typename
basic_path<String, Traits>::string_type::value_type* b</code></span></td>
</tr>
</table>
<p><span style="background-color: #FFFFFF">In the </span><b><i>
<span style="background-color: #FFFFFF">basic_path non-member operators </span>
</i></b><span style="background-color: #FFFFFF">table, </span><code>
<span style="background-color: #FFFFFF">a</span></code><span style="background-color: #FFFFFF">
and </span><code><span style="background-color: #FFFFFF">b</span></code><span style="background-color: #FFFFFF">
are of the types given in the </span><i><b>
<span style="background-color: #FFFFFF">Argument type overloads</span></b></i><span style="background-color: #FFFFFF">
table. If </span><code><span style="background-color: #FFFFFF">a</span></code><span style="background-color: #FFFFFF">
or </span><code><span style="background-color: #FFFFFF">b</span></code><span style="background-color: #FFFFFF">
is of type </span><code><span style="background-color: #FFFFFF">const
basic_path<String, Traits>&</span></code><span style="background-color: #FFFFFF">,
then </span><i><b><span style="background-color: #FFFFFF">a</span></b></i><code><i><b><span style="background-color: #FFFFFF">'</span></b></i></code><span style="background-color: #FFFFFF">
or </span><i><b><span style="background-color: #FFFFFF">b'</span></b></i><span style="background-color: #FFFFFF">
respectively is </span><code><span style="background-color: #FFFFFF">a</span></code><span style="background-color: #FFFFFF">
or </span><code><span style="background-color: #FFFFFF">b</span></code><span style="background-color: #FFFFFF">
respectively. Otherwise </span><i><b><span style="background-color: #FFFFFF">a</span></b></i><code><i><b><span style="background-color: #FFFFFF">'</span></b></i></code><span style="background-color: #FFFFFF">
or </span><i><b><span style="background-color: #FFFFFF">b'</span></b></i><span style="background-color: #FFFFFF">
respectively represent named or unnamed temporary </span><code>
<span style="background-color: #FFFFFF">basic_path<String, Traits></span></code><span style="background-color: #FFFFFF">
objects constructed from </span><code><span style="background-color: #FFFFFF">
a</span></code><span style="background-color: #FFFFFF"> or </span><code>
<span style="background-color: #FFFFFF">b</span></code><span style="background-color: #FFFFFF">
respectively.</span></p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" height="280">
<tr>
<td width="100%" colspan="3" align="center" height="19"><b><i>
<span style="background-color: #FFFFFF">basic_path non-member operators</span></i></b></td>
</tr>
<tr>
<td width="20%" align="center" height="19"><i><b>
<span style="background-color: #FFFFFF">Expression</span></b></i></td>
<td width="25%" align="center" height="19"><i><b>
<span style="background-color: #FFFFFF">Return type</span></b></i></td>
<td width="55%" align="center" height="19"><i><b>
<span style="background-color: #FFFFFF">Semantics</span></b></i></td>
</tr>
<tr>
<td width="20%" align="center" height="30" valign="top"><code>
<span style="background-color: #FFFFFF">a / b</span></code></td>
<td width="25%" align="center" height="30" valign="top"><code>
<span style="background-color: #FFFFFF">basic_path<String, Traits></span></code></td>
<td width="55%" height="30"><code><span style="background-color: #FFFFFF">
basic_path<String, Traits> tmp(a);<br>
return tmp /= </span></code><i><b><span style="background-color: #FFFFFF">b'</span></b></i><code><span style="background-color: #FFFFFF">;</span></code></td>
</tr>
<tr>
<td width="20%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">a < b</span></code></td>
<td width="25%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">bool</span></code></td>
<td width="55%" height="19"><code><span style="background-color: #FFFFFF">
return lexicographical_compare(</span></code><span style="background-color: #FFFFFF"><i><b>a</b></i></span><code><span style="background-color: #FFFFFF"><i><b>'</b></i>.begin(), </span></code><i><b>
<span style="background-color: #FFFFFF">a</span></b></i><code><span style="background-color: #FFFFFF"><i><b>'</b></i>.end(), </span></code><i><b>
<span style="background-color: #FFFFFF">b'</span></b></i><code><span style="background-color: #FFFFFF">.begin(), </span></code><i><b>
<span style="background-color: #FFFFFF">b'</span></b></i><code><span style="background-color: #FFFFFF">.end());</span></code></td>
</tr>
<tr>
<td width="20%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">a == b</span></code></td>
<td width="25%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">bool</span></code></td>
<td width="55%" height="19"><code><span style="background-color: #FFFFFF">
return !(</span></code><i><b><span style="background-color: #FFFFFF">a</span></b></i><code><i><b><span style="background-color: #FFFFFF">'</span></b></i><span style="background-color: #FFFFFF">
< </span></code><i><b><span style="background-color: #FFFFFF">b'</span></b></i><code><span style="background-color: #FFFFFF">)
&& !(</span></code><i><b><span style="background-color: #FFFFFF">b'</span></b></i><code><span style="background-color: #FFFFFF">
< </span></code><i><b><span style="background-color: #FFFFFF">a</span></b></i><code><i><b><span style="background-color: #FFFFFF">'</span></b></i><span style="background-color: #FFFFFF">);</span></code></td>
</tr>
<tr>
<td width="20%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">a != b</span></code></td>
<td width="25%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">bool</span></code></td>
<td width="55%" height="19"><code><span style="background-color: #FFFFFF">
return !(</span></code><i><b><span style="background-color: #FFFFFF">a</span></b></i><code><i><b><span style="background-color: #FFFFFF">'</span></b></i><span style="background-color: #FFFFFF">
== </span></code><i><b><span style="background-color: #FFFFFF">b'</span></b></i><code><span style="background-color: #FFFFFF">);</span></code></td>
</tr>
<tr>
<td width="20%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">a > b</span></code></td>
<td width="25%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">bool</span></code></td>
<td width="55%" height="19"><code><span style="background-color: #FFFFFF">
return </span></code><i><b><span style="background-color: #FFFFFF">b'</span></b></i><code><span style="background-color: #FFFFFF">
< </span></code><i><b><span style="background-color: #FFFFFF">a</span></b></i><code><i><b><span style="background-color: #FFFFFF">'</span></b></i><span style="background-color: #FFFFFF">;</span></code></td>
</tr>
<tr>
<td width="20%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">a <= b</span></code></td>
<td width="25%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">bool</span></code></td>
<td width="55%" height="19"><code><span style="background-color: #FFFFFF">
return !(</span></code><i><b><span style="background-color: #FFFFFF">b'</span></b></i><code><span style="background-color: #FFFFFF">
< </span></code><i><b><span style="background-color: #FFFFFF">a</span></b></i><code><i><b><span style="background-color: #FFFFFF">'</span></b></i><span style="background-color: #FFFFFF">);</span></code></td>
</tr>
<tr>
<td width="20%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">a >= b</span></code></td>
<td width="25%" align="center" height="19" valign="top"><code>
<span style="background-color: #FFFFFF">bool</span></code></td>
<td width="55%" height="19"><code><span style="background-color: #FFFFFF">
return !(</span></code><i><b><span style="background-color: #FFFFFF">a</span></b></i><code><i><b><span style="background-color: #FFFFFF">'</span></b></i><span style="background-color: #FFFFFF">
< </span></code><i><b><span style="background-color: #FFFFFF">b'</span></b></i><code><span style="background-color: #FFFFFF">);</span></code></td>
</tr>
</table>
<blockquote>
<p><span style="background-color: #FFFFFF">[</span><i><span style="background-color: #FFFFFF">Note:</span></i><span style="background-color: #FFFFFF">
</span> <a name="Path-equality"><span style="background-color: #FFFFFF">Path equality</span></a><span style="background-color: #FFFFFF"> and path
equivalence have different semantics.</span></p>
<p><span style="background-color: #FFFFFF">Equality is determined by </span> <i>
<span style="background-color: #FFFFFF">basic_path</span></i><span style="background-color: #FFFFFF">'s
non-member </span> <code><a href="#operator-eq">
<span style="background-color: #FFFFFF">operator==</span></a></code><span style="background-color: #FFFFFF">, which considers the two path's lexical representations
only. Paths "abc" and "ABC" are never equal.</span></p>
<p><span style="background-color: #FFFFFF">Equivalence is determined by the
</span> <a href="#equivalent"><span style="background-color: #FFFFFF">equivalent()</span></a><span style="background-color: #FFFFFF">
non-member function, which determines if two paths </span>
<a href="#pathname-resolution"><span style="background-color: #FFFFFF">resolve</span></a><span style="background-color: #FFFFFF"> to the same file system entity.
Paths "abc"
and "ABC" may or may not resolve to the same file, depending on the file
system.</span></p>
<p><span style="background-color: #FFFFFF">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. </span> <i>
<span style="background-color: #FFFFFF">-- end note</span></i><span style="background-color: #FFFFFF">]</span></p>
</blockquote>
<h4><a name="basic_path-inserter-extractor"> <code>
<span style="background-color: #FFFFFF">basic_path</span></code><span style="background-color: #FFFFFF"> inserter
and extractor</span></a></h4>
<pre><span style="background-color: #FFFFFF">template<class Path>
basic_istream<typename Path::string_type::value_type, typename Path::string_type::traits_type>&
operator>>(basic_istream< typename Path::string_type::value_type, typename Path::string_type::traits_type>& is,
Path& ph );</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Effects: </span></i>
<code><span style="background-color: #FFFFFF">typename Path::string_type str;<br>
is >> str;<br>
ph = str;</span></code></p>
<p><i><span style="background-color: #FFFFFF">Returns:</span></i><span style="background-color: #FFFFFF">
</span> <code><span style="background-color: #FFFFFF">is</span></code></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">template<class Path>
basic_ostream<typename Path::string_type::value_type, typename Path::string_type::traits_type>&
operator<<(basic_ostream< typename Path::string_type::value_type, typename Path::string_type::traits_type>& os,
const Path& ph );</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Effects:</span></i><span style="background-color: #FFFFFF">
</span> <code><span style="background-color: #FFFFFF">os << ph.string()</span></code></p>
<p><i><span style="background-color: #FFFFFF">Returns:</span></i><span style="background-color: #FFFFFF">
</span> <code><span style="background-color: #FFFFFF">os</span></code></p>
</blockquote>
<h3><a name="Class-template-basic_filesystem_error">Class template <code>basic_filesystem_error</code></a></h3>
<pre> namespace boost
{
namespace filesystem
{
template <class Path> class basic_filesystem_error : public <span style="background-color: #FFFFFF">system</span>_error
{
public:
typedef Path path_type;
explicit basic_filesystem_error(const std::string& <span style="background-color: #FFFFFF">what_arg</span>, error_code ec);
basic_filesystem_error(const std::string& <span style="background-color: #FFFFFF">what_arg</span>, const path_type& p1, error_code ec);
basic_filesystem_error(const std::string& <span style="background-color: #FFFFFF">what_arg</span>, const path_type& p1, const path_type& p2, error_code ec);
const path_type& path1() const;
const path_type& path2() const;
const char * what() const;
};
} // namespace filesystem
} // namespace boost</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
clause.</p>
<h4> <a name="basic_filesystem_error-constructors"> <code>basic_filesystem_error</code> constructors</a></h4>
<pre>explicit basic_filesystem_error(const std::string& <span style="background-color: #FFFFFF">what_arg</span>, error_code ec);</pre>
<blockquote>
<p><i>Postconditions:</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>
<span style="background-color: #FFFFFF">runtime_error::what</span>()</code></td>
<td width="82%" bgcolor="#FFFFFF"><span style="background-color: #FFFFFF">
<code><i>what_arg</i>.c_str()</code></span></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>basic_filesystem_error(const std::string& <span style="background-color: #FFFFFF">what_arg</span>, const path_type& p1, error_code ec);</pre>
<blockquote>
<p><i>Postconditions:</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>
<span style="background-color: #FFFFFF">runtime_error::what</span>()</code></td>
<td width="82%"><span style="background-color: #FFFFFF">
<code><i>what_arg</i>.c_str()</code></span></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%"><span style="background-color: #FFFFFF">Reference to stored copy of
</span> <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>basic_filesystem_error(const std::string& <span style="background-color: #FFFFFF">what_arg</span>, const path_type& p1, const path_type& p2, error_code ec);</pre>
<blockquote>
<p><i>Postconditions:</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>
<span style="background-color: #FFFFFF">runtime_error::what</span>()</code></td>
<td width="82%"><span style="background-color: #FFFFFF">
<u>
<code><i>w</i></code></u><code><i>hat_arg</i>.c_str()</code></span></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%"><span style="background-color: #FFFFFF">Reference to stored copy of
</span> <code>p1</code></td>
</tr>
<tr>
<td width="18%"><code>path2()</code></td>
<td width="82%"><span style="background-color: #FFFFFF">Reference to stored copy of
</span> <code>p2</code></td>
</tr>
</table>
</blockquote>
<h4> <a name="basic_filesystem_error-observers"> <code>basic_filesystem_error</code> observers</a></h4>
<pre>const path_type& path1() 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_type& path2() 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 * what() const;</pre>
<blockquote>
<p><i>Returns: </i>A string containing <code>runtime_error::what()</code> and
the result of calling <code>system_message()</code> with a first argument of
<code>code()</code>. The exact format is unspecified.</p>
<p>The implementation shall supply a specialization <code>template<> const char
* basic_filesystem_error<path>::what() const</code> that returns a string
containing <code>runtime_error::what(),</code> the result of calling <code>
system_message()</code> with a first argument of <code>code()</code>, and if
non-empty, <code>path1().file_string()</code> and <code>path2.file_string()</code>.
The exact format is unspecified.</p>
<p>Implementations and users are permitted to provide other specializations of
the <code>what</code> member function.</p>
</blockquote>
<h3><a name="Class-template-basic_directory_entry">Class template <code>basic_directory_entry</code></a></h3>
<pre> namespace boost
{
namespace filesystem
{
template <class Path> class basic_directory_entry
{
public:
typedef Path path_type;
typedef typename Path::string_type string_type;
// <a href="#basic_directory_entry-constructors">constructors</a>
basic_directory_entry();
explicit basic_directory_entry(const path_type& p,
<span style="background-color: #FFFFFF">file_status</span> st=file_status(), <span style="background-color: #FFFFFF">file_status</span> symlink_st=file_status());
// <a href="#basic_directory_entry-modifiers">modifiers</a>
void assign(const path_type& p, <span style="background-color: #FFFFFF">file_status</span> st=file_status(), <span style="background-color: #FFFFFF">file_status</span> symlink_st=file_status());
void replace_filename(const string_type& s, <span style="background-color: #FFFFFF">file_status</span> st=file_status(), <span style="background-color: #FFFFFF">file_status</span> symlink_st=file_status());
// <a href="#basic_directory_entry-observers">observers</a>
const Path& path() const;
operator const Path&() const;
<span style="background-color: #FFFFFF">
file_status status() const;
file_status status(error_code& ec) const;
file_status symlink_status() const;
file_status symlink_status(error_code& ec) const;
</span><span style="background-color: #FFFF00">
</span> // <a href="#basic_directory_entry-comparisons">comparisons</a>
bool operator<(const basic_directory_entry<Path>& rhs);
bool operator==(const basic_directory_entry<Path>& rhs);
bool operator!=(const basic_directory_entry<Path>& rhs);
bool operator>(const basic_directory_entry<Path>& rhs);
bool operator<=(const basic_directory_entry<Path>& rhs);
bool operator>=(const basic_directory_entry<Path>& rhs);
private:
path_type m_path; // for exposition only
mutable <span style="background-color: #FFFFFF">file_status</span> m_status; // for exposition only; stat()-like
mutable <span style="background-color: #FFFFFF">file_status</span> m_symlink_status; // for exposition only; lstat()-like
};
} // namespace filesystem
} // namespace boost</pre>
<p>A <code>basic_directory_entry</code> object stores a <code>basic_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 race conditions. <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 speedup expected on Linux and BSD-derived
Unix variants that provide status during directory iteration.</i></span></p>
</blockquote>
<h4> <a name="basic_directory_entry-constructors"> <code>basic_directory_entry </code>constructors</a></h4>
<pre>basic_directory_entry();</pre>
<blockquote>
<p><i>Postconditions:</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 basic_directory_entry(const path_type& p, <span style="background-color: #FFFFFF">file_status</span> st=file_status(), <span style="background-color: #FFFFFF">file_status</span> symlink_st=file_status());</pre>
<blockquote>
<p><i>Postconditions:</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="basic_directory_entry-modifiers"> <code>basic_directory_entry </code>modifiers</a></h4>
<pre>void assign(const path_type& p, <span style="background-color: #FFFFFF">file_status</span> st=file_status(), <span style="background-color: #FFFFFF">file_status</span> symlink_st=file_status());</pre>
<blockquote>
<p><i>Postconditions:</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 string_type& s, <span style="background-color: #FFFFFF">file_status</span> st=file_status(), <span style="background-color: #FFFFFF">file_status</span> symlink_st=file_status());</pre>
<blockquote>
<p><i>Postconditions:</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="basic_directory_entry-observers"> <code>basic_directory_entry</code> observers</a></h4>
<pre>const Path& path() const;
operator const Path&() const;</pre>
<blockquote>
<p><i>Returns:</i> <code>m_path</code></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">file_status status() const;</span></pre>
<blockquote>
<p><span style="font-style: italic; background-color: #FFFFFF">Effects:</span><span style="background-color: #FFFFFF">
As if,</span></p>
<blockquote>
<pre><span style="background-color: #FFFFFF">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); }
}</span></pre>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>Throws:</i> See <code>status</code>
function.</span></p>
<p><span style="background-color: #FFFFFF"><i>Returns:</i> <code>m_status</code></span></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">file_status status(error_code& ec) const;</span></pre>
<blockquote>
<p><span style="font-style: italic; background-color: #FFFFFF">Effects:</span><span style="background-color: #FFFFFF">
As if,</span></p>
<blockquote>
<pre><span style="background-color: #FFFFFF">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, ec); }
}
else ec = 0;</span></pre>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>Returns:</i> <code>m_status</code></span></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">file_status symlink_status() const;</span></pre>
<blockquote>
<p><span style="font-style: italic; background-color: #FFFFFF">Effects:</span><span style="background-color: #FFFFFF">
As if,</span></p>
<blockquote>
<pre><span style="background-color: #FFFFFF">if ( !status_known( m_symlink_status ) )
{
m_symlink_status = symlink_status(m_path);
}</span></pre>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>Throws:</i> See <code>symlink_status</code>
function.</span></p>
<p><span style="background-color: #FFFFFF"><i>Returns:</i> <code>
m_symlink_status</code></span></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">file_status symlink_status(error_code& ec) const;</span></pre>
<blockquote>
<p><span style="font-style: italic; background-color: #FFFFFF">Effects:</span><span style="background-color: #FFFFFF">
As if,</span></p>
<blockquote>
<pre><span style="background-color: #FFFFFF">if ( !status_known( m_symlink_status ) )
{
m_symlink_status = symlink_status(m_path, ec);
}
else ec = 0;</span></pre>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>Returns:</i> <code>m_symlink_status</code></span></p>
</blockquote>
<h3><a name="Class-template-basic_directory_iterator">Class template <code>basic_directory_iterator</code></a></h3>
<pre> namespace boost
{
namespace filesystem
{
template <class Path>
class basic_directory_iterator :
public iterator<input_iterator_tag, basic_directory_entry<Path> >
{
public:
typedef Path path_type;
// <a href="#basic_directory_iterator-constructors">constructors</a>
basic_directory_iterator();
explicit basic_directory_iterator(const Path& dp);
basic_directory_iterator(const Path& dp, error_code& ec);
basic_directory_iterator(const basic_directory_iterator& bdi);
basic_directory_iterator& operator=(const basic_directory_iterator& bdi);
~basic_directory_iterator();
// other members as required by
// C++ Std, 24.1.1 Input iterators [lib.input.iterators]
};
} // namespace filesystem
} // namespace boost</pre>
<p> <code>basic_directory_iterator</code> satisfies the requirements of an
input iterator (C++ Std, 24.1.1, Input iterators [lib.input.iterators]).</p>
<p>A <code>basic_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>basic_directory_iterator</code> is constructed, and every time
<code>operator++</code> is called,
it reads and stores a value of <code>basic_directory_entry<Path></code>
and possibly stores associated status values.
<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 be used only 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>basic_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 basic_directory_entry<Path>&</code> is returned. The result of
<code>operator-></code> on an end iterator is not defined. For any other
iterator value a <code>const basic_directory_entry<Path>*</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. Commentary was shortened and
moved into a note.</span></i></p>
</blockquote>
<p>The result of calling the <code>path()</code> member of the <code>
basic_directory_entry</code> object obtained by dereferencing a <code>
basic_directory_iterator</code> is a reference to a <code>basic_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>
<blockquote>
<p>[<i><a name="Example-program">Example</a>: </i>This program accepts an
optional command line argument, and if that argument is a directory pathname,
iterates over the contents of the directory. For each directory entry, the name
is output, and if the entry is for a regular file, the size of the file is
output.</p>
<blockquote>
<pre>#include <iostream>
#include <filesystem>
using std::tr2::sys;
using std::cout;
int main(int argc, char* argv[])
{
std::string p(argc <= 1 ? "." : argv[1]);
if (is_directory(p))
{
for (directory_iterator itr(p); itr!=directory_iterator(); ++itr)
{
cout << itr->path().filename() << ' '; // display filename only
if (is_regular_file(itr->status())) cout << " [" << file_size(itr->path()) << ']';
cout << '\n';
}
}
else cout << (exists(p) ? "Found: " : "Not found: ") << p << '\n';
return 0;
}</pre>
</blockquote>
<p><i>-- end example</i>]</p>
</blockquote>
<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>basic_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>basic_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="basic_directory_iterator-constructors"><code>basic_directory_iterator</code> constructors</a></h4>
<p><code>basic_directory_iterator();</code></p>
<blockquote>
<p><i>Effects:</i> Constructs the end iterator.</p>
</blockquote>
<p><code>explicit basic_directory_iterator(const Path& dp);</code></p>
<blockquote>
<p><i>Effects:</i> Constructs a iterator representing the first
entry in the directory resolved to by <code>dp</code>, otherwise, the end iterator.</p>
<p>[<i>Note:</i> To iterate over the current directory, write <code>
directory_iterator(".")</code> rather than <code>directory_iterator("")</code>.
<i>-- end note</i>]</p>
</blockquote>
<pre><code>basic_directory_iterator(const Path& dp, error_code& ec );</code></pre>
<blockquote>
<p><i>Effects:</i> Constructs a iterator representing the first
entry in the directory resolved to by <code>dp</code>, otherwise, the end iterator.
If an error occurs while establishing the results, the iterator constructed
represents the end iterator and <code>ec</code> is set to the error code
reported by the operating system, otherwise to 0.</p>
</blockquote>
<h3><a name="Class-template-basic_recursive_directory_iterator">Class template <code>basic_recursive_directory_iterator</code></a></h3>
<pre> namespace boost
{
namespace filesystem
{
template <class Path>
class basic_recursive_directory_iterator :
public iterator<input_iterator_tag, basic_directory_entry<Path> >
{
public:
typedef Path path_type;
// constructors
basic_recursive_directory_iterator();
explicit basic_recursive_directory_iterator(const Path& dp);
basic_recursive_directory_iterator(const basic_recursive_directory_iterator& brdi);
basic_recursive_directory_iterator& operator=(const basic_recursive_directory_iterator& brdi);
~basic_recursive_directory_iterator();
// observers
int level() const;
// modifiers
void pop();
void no_push();
// other members as required by
// C++ Std, 24.1.1 Input iterators [lib.input.iterators]
private:
int m_level; // for exposition only
};
} // namespace filesystem
} // namespace boost</pre>
<p>The behavior of a <code>basic_recursive_directory_iterator</code> is the same
as a <code>basic_directory_iterator</code> unless otherwise specified.</p>
<ul>
<li>When an iterator is constructed, <code>m_level</code> is set to 0;</li>
<li>When an iterator <code>it</code> is incremented, if <code>it->is_directory()</code>
is true and <code>no_push()</code> had not been called subsequent to
the most recent increment operation (or construction, if no increment has
occurred), then <code>m_level</code> is incremented, the
directory is visited, and its contents recursively iterated over.</li>
<li>When an iterator 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 continues with the parent directory, until the
directory specified in the constructor argument is reached.</li>
<li><code>level()</code> returns <code>m_level</code>.</li>
<li><code>level()</code>, <code>pop()</code>, and <code>no_push()</code> all
require that the iterator not be the end iterator.</li>
</ul>
<blockquote>
<p>[<i>Note:</i> One of the uses of <code>no_push()</code> is to prevent
unwanted recursion into symlinked directories. This may be necessary to
prevent loops on some operating systems. <i>--end note</i>]</p>
</blockquote>
<h3><a name="file_status">Class file_status</a></h3>
<pre> namespace boost
{
namespace filesystem
{
class file_status
{
public:
explicit file_status( file_type v = status_unknown );
file_type type() const;
void type( file_type v );
};
} // namespace filesystem
} // namespace boost</pre>
<p>A <code>file_status</code> object stores information about the status of a
file. The internal form of the stored information is unspecified.</p>
<blockquote>
<p><i>[Note: </i>The class may be extended in the future to store
additional status information. <i>--end note]</i></p>
</blockquote>
<h4>Members</h4>
<pre>explicit file_status( file_type v = status_unknown );</pre>
<blockquote>
<p><i>Effects:</i> Stores <code>v</code>.</p>
</blockquote>
<pre>file_type type() const;</pre>
<blockquote>
<p><i>Returns: </i>The stored <code>file_type</code>.</p>
</blockquote>
<pre>void type( file_type v );</pre>
<blockquote>
<p><i>Effects:</i> Stores <code>v</code>, replacing the previously stored
value.</p>
</blockquote>
<h3><a name="Non-member-functions">Non-member operational functions</a></h3>
<h4><a name="Status-functions">Status functions</a></h4>
<pre>template <class Path> file_status status(const Path& p, error_code& ec);
template <class Path> file_status <a name="symlink_status">symlink_status</a>(const Path& p, error_code& ec);</pre>
<blockquote>
<p><i>Returns:</i></p>
<blockquote>
For <code>status</code>, determine the attributes
of
<code>p</code> as if by<i> POSIX </i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/stat.html">stat()</a></code>,
for <code>symlink_status</code>, determine the attributes as if by <i>POSIX </i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/lstat.html">
lstat()</a></code>.<blockquote>
<p>[<i>Note:</i> For symbolic links, <code>stat()</code> continues
pathname resolution using the contents of the symbolic link, <code>lstat()</code>
does not. <i>--
end note</i>]</p>
</blockquote>
<p>If the underlying file system reports an error during attribute determination:</p>
<ul>
<li>If the error indicating that <code>p</code> could not be resolved, as
if by POSIX errors ENOENT or ENOTDIR, call <code>ec.clear()</code> and return <code>
file_status(not_found_flag)</code>.</li>
</ul>
<blockquote>
<blockquote>
<p>[<i>Note:</i> The effect of this behavior is to distinguish between
knowing that p
does not exist, and not being able to determine the status of p. This
distinction is important to users. <i>--end note</i>]</p>
</blockquote>
</blockquote>
<ul>
<li>Otherwise, set ec to the error number reported by the underlying
implementation API
and return <code>
file_status(status_unknown)</code>.</li>
</ul>
Otherwise:<ul>
<li>If the attributes indicate a regular file, as if by <i>POSIX</i> S_<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">ISREG()</a>,
return <code>
file_status(regular_file)</code>.</li>
<li>Else if the attributes indicate a directory, as if by <i>POSIX</i> S_<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">ISDIR()</a>,
return <code>
file_status(directory_file)</code>.</li>
<li>Else if the attributes indicate a symbolic link, as if by <i>POSIX</i> S_<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">ISLNK()</a>,
return <code>
file_status(symlink_file)</code>. <i>[Note: </i>Only possible for <code>
symlink_status</code>. <i>--end note]</i></li>
<li>Else if the attributes indicate a block special file, as if by <i>POSIX</i> S_<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">ISBLK()</a>,
return <code>
file_status(block_file)</code>.</li>
<li>Else if the attributes indicate a character special file, as if by <i>POSIX</i> S_<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">ISCHR()</a>,
return <code>
file_status(character_file)</code>.</li>
<li>Else if the attributes indicate a fifo or pipe file, as if by <i>POSIX</i> S_<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">ISFIFO()</a>,
return <code>
file_status(fifo_file)</code>.</li>
<li>Else if the attributes indicate a socket, as if by <i>POSIX</i> S_<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html">ISSOCK()</a>,
return <code>
file_status(socket_file)</code>.</li>
<li>Else return <code>
file_status(type_unknown)</code>.</li>
</ul>
</blockquote>
<p>[<i>Note:</i> <code>directory_file</code> implies <code>
basic_directory_iterator</code> on the file would succeed, and <code>
regular_file</code> implies appropriate <code><fstream></code> operations would succeed,
assuming no hardware, permission, access, or race
condition errors. For <code>regular_file,</code> the converse is not true; lack of
<code>regular_file</code> does not necessarily imply <code><fstream></code> operations would
fail on a directory.
<i>-- end note</i>]</p>
</blockquote>
<pre>template <class Path> file_status status(const Path& p);</pre>
<blockquote>
<p><i>Effects:</i> <code>system_error_code ec;</code><br>
<code>file_status stat(status(p, ec));</code></p>
<p><i>Throws:</i> <code>basic_filesystem_error<Path></code> if <code>ec
!= 0</code></p>
<p><i>Returns:</i> <code>stat</code></p>
</blockquote>
<pre>template <class Path> file_status symlink_status(const Path& p);</pre>
<blockquote>
<p><i>Effects:</i> <code>system_error_code ec;</code><br>
<code>file_status stat(symlink_status(p, ec));</code></p>
<p><i>Throws:</i> <code>basic_filesystem_error<Path></code> if <code>ec
!= 0</code></p>
<p><i>Returns: </i><code>stat</code></p>
</blockquote>
<h4><a name="Predicate-functions">Predicate functions</a></h4>
<pre><span style="background-color: #FFFFFF">bool <a name="status_known">status_known</a>(file_status s);</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Returns:</span></i><span style="background-color: #FFFFFF">
<code>s.type() != status_unknown</code></span></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">bool </span><a name="exists"><span style="background-color: #FFFFFF">exists</span></a><span style="background-color: #FFFFFF">(file_status</span><span style="background-color: #FFFFFF"> s);</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Returns:</span></i><span style="background-color: #FFFFFF">
<code>status_known(s) && s.type() != file_not_found</code></span></p>
</blockquote>
<pre>template <class Path> bool <a name="exists">exists</a>(const Path& p);</pre>
<blockquote>
<p><i>Returns:</i> <code>exists( status(p) )</code></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">bool </span><code><span style="background-color: #FFFFFF">is_regular_file</span></code><span style="background-color: #FFFFFF">(file_status</span><span style="background-color: #FFFFFF"> s);</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Returns:</span></i><span style="background-color: #FFFFFF">
<code>s.type() == regular_file</code></span></p>
</blockquote>
<pre><code>template <class Path> bool is_regular_file(const Path& p);</code></pre>
<blockquote>
<p><i>Returns:</i> <code>is_regular_file( status(p) )</code></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">bool </span><code><span style="background-color: #FFFFFF">is_directory</span></code><span style="background-color: #FFFFFF">(file_status</span><span style="background-color: #FFFFFF"> s);</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Returns:</span></i><span style="background-color: #FFFFFF"> </span>
<code><span style="background-color: #FFFFFF">s.type() == directory_file</span></code></p>
</blockquote>
<pre><code>template <class Path> bool is_directory(const Path& p);</code></pre>
<blockquote>
<p><i>Returns:</i> <code>is_directory( status(p) )</code></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">bool <a name="exists">is_symlink</a>(file_status s);</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Returns:</span></i><span style="background-color: #FFFFFF"> </span>
<code><span style="background-color: #FFFFFF">s.type() == symlink_file</span></code></p>
</blockquote>
<pre><code>template <class Path> bool is_symlink(const Path& p);</code></pre>
<blockquote>
<p><i>Returns:</i> <code>is_symlink( symlink_status(p) )</code></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">bool <a name="exists">is_other</a>(file_status s);</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Returns:</span></i><span style="background-color: #FFFFFF">
<code>return exists(s) && !is_regular_file(s) && !is_directory(s) && !is_symlink(s)</code></span></p>
<p><span style="background-color: #FFFFFF">[<i>Note: </i>The specification of
<code>is_other()</code> will remain unchanged even if additional <code>is_xxx()</code>
functions are added in the future. <i>-- end note</i>]</span></p>
</blockquote>
<pre><code>template <class Path> bool is_other(const Path& p);</code></pre>
<blockquote>
<p><i>Returns:</i> <code>is_other( status(p) )</code></p>
</blockquote>
<pre><code>template <class Path> bool <span style="background-color: #FFFFFF; text-decoration:underline">is_</span>empty(const Path& p);</code></pre>
<blockquote>
<p><i>Effects:</i> Determines <code>file_status s</code>, as if by <code>
status(p)</code>.</p>
<p><i>Throws:</i> <code>basic_filesystem_error<Path></code> if <code>!exist(s) ||
is_other(s)</code>.</p>
<p><i>Returns:</i> <code>is_directory(s)<br>
?
basic_directory_iterator<Path>(p) == basic_directory_iterator<Path>()<br>
: file_size(p) == 0;</code></p>
</blockquote>
<pre><code>template <class Path1, class Path2> bool <a name="equivalent">equivalent</a>(const Path1& p1, const Path2& p2);</code></pre>
<blockquote>
<p><i>Requires:</i> <code>Path1::external_string_type</code> and <code>
Path2::external_string_type</code> are the same type. </p>
<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>Throws:</i> <code>basic_filesystem_error<Path1></code><span style="background-color: #FFFFFF"> </span>
if <code>(!exists(s1) && !exists(s2)) || (is_other(s1) &&
is_other(s2))</code>.</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>
<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>
<h4><a name="Attribute-functions">Attribute functions</a></h4>
<p>[<i>Note:</i> A strictly limited number of attribute functions are provided
because few file system attributes are portable. Even the functions provided will be impossible to implement on some file
systems. <i>--end note</i>.]</p>
<pre>template <class Path> const Path& <a name="initial_path">initial_path</a>();</pre>
<blockquote>
<p><i>Returns:</i> <code>current_path()</code> at the time of entry to <code>
main()</code>.</p>
<p>[<i>Note:</i> These semantics turn a dangerous global variable into a safer
global constant. <i>--end note</i>]</p>
<p>[<i>Note:</i> Full implementation requires runtime library support.
Implementations which cannot provide runtime library support are encouraged to
instead store the value of <code>current_path()</code> at the first call of
<a name="initial_path"><code>initial_path</code></a><code>()</code>, and
return this value for all subsequent calls. Programs using
<a name="initial_path"><code>initial_path</code></a><code>()</code> are
encouraged to call it immediately on entrance to <code>main()</code> so that
they will work correctly with such partial implementations. <i>--end note</i>]</p>
</blockquote>
<pre>template <class Path> Path current_path();</pre>
<blockquote>
<p><i>Returns:</i> The current path, as if by <i>POSIX</i>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/getcwd.html">
<code>getcwd()</code></a>.</p>
<p><i>Postcondition:</i> <code>current_path().is_complete()</code></p>
<p>[<i>Note:</i> 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. Although dangerous, the
function is useful in dealing with other libraries.. For a safer alternative,
see <code><a href="#initial_path">initial_path()</a></code>. The <code>
current_path()</code> name was chosen to emphasize that the return is a
complete path, not just a single directory name. <i>-- </i><i>end note</i>]</p>
</blockquote>
<pre>template <class Path> void current_path(const Path& p);</pre>
<blockquote>
<p><i>Postcondition:</i> equivalent( p, current_path() );</p>
</blockquote>
<pre>template <class Path> <span style="background-color: #FFFFFF; ">uintmax_t</span> file_size(const Path& p);</pre>
<blockquote>
<p><i>Returns:</i> The size
<span style="background-color: #FFFFFF; ">in bytes</span>
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>.</p>
</blockquote>
<pre><span style="background-color: #FFFFFF"><a name="space">template</a> <class Path> space_info space(const Path& p);</span></pre>
<blockquote>
<p><span style="background-color: #FFFFFF"><i>Returns:</i> A <code>space_info</code>
object. The value of the <code>space_info</code> object is determined as if by
using </span> <i><span style="background-color: #FFFFFF">POSIX</span></i><span style="background-color: #FFFFFF"> <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.</span></p>
</blockquote>
<pre>template <class Path> std::time_t last_write_time(const Path& p);</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>
</blockquote>
<pre>template <class Path> void last_write_time(const Path& p, const std::time_t new_time);</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>Note:</i> The apparent postcondition <code>last_write_time(p) ==
new_time</code> is not specified since it would not hold for many file systems
due to coarse time mechanism granularity. <i>-- end note</i>]</p>
</blockquote>
<h4>Other o<a name="Operations-functions">perations functions</a></h4>
<pre>template <class Path> bool create_directory(const Path& dp);</pre>
<blockquote>
<p><i>Effects:</i> Attempts to create the directory <code>dp</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>Throws:</i> <code>basic_filesystem_error<Path></code> if <i>
Effects</i> fails for any reason other than because the directory already exists.</p>
<p><i>Returns:</i> True if a new directory was created, otherwise false.</p>
<p><i>Postcondition:</i> <code>is_directory(dp)</code></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">template <class Path1, class Path2>
error_code create_hard_link(const Path1& to_p, const Path2& from_p, error_code& ec);</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Requires:</span></i><span style="background-color: #FFFFFF">
</span> <code><span style="background-color: #FFFFFF">Path1::external_string_type</span></code><span style="background-color: #FFFFFF"> and
</span> <code>
<span style="background-color: #FFFFFF">Path2::external_string_type</span></code><span style="background-color: #FFFFFF"> are the same type.</span></p>
<p><i><span style="background-color: #FFFFFF">Effects:</span></i><span style="background-color: #FFFFFF"> Establishes the postcondition, as if by
</span> <i><span style="background-color: #FFFFFF">POSIX</span></i><span style="background-color: #FFFFFF">
</span> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/link.html">
<span style="background-color: #FFFFFF">link()</span></a></code><span style="background-color: #FFFFFF">.</span></p>
<p><i><span style="background-color: #FFFFFF">Returns:</span></i><span style="background-color: #FFFFFF"> If the
postcondition cannot be established, a system error code
indicating the reason for the failure, otherwise 0.</span></p>
<p><i><span style="background-color: #FFFFFF">Postcondition:</span></i></p>
<ul>
<li><span style="background-color: #FFFFFF"> </span><code><span style="background-color: #FFFFFF">exists(to_p) && exists(from_p) && equivalent(to_p,
from_p)</span></code></li>
<li><span style="background-color: #FFFFFF">The contents of the file or directory
</span> <code><span style="background-color: #FFFFFF">to_p</span></code><span style="background-color: #FFFFFF"> resolves to are unchanged.</span></li>
</ul>
<p><span style="background-color: #FFFFFF">[</span><i><span style="background-color: #FFFFFF">Note:</span></i><span style="background-color: #FFFFFF">
Some operating systems do not support hard links or support
them only for regular files. Some operating systems limit the number of links per
file.
Some file systems that do not
support
hard links - the FAT system used on floppy discs, memory cards and flash
drives,
for example. Thus hard links should be avoided if wide portability is
a concern. </span> <i><span style="background-color: #FFFFFF">-- end note</span></i><span style="background-color: #FFFFFF">]</span></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">template <class Path1, class Path2>
void create_hard_link(const Path1& to_p, const Path2& from_p);</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Requires:</span></i><span style="background-color: #FFFFFF">
</span> <code><span style="background-color: #FFFFFF">Path1::external_string_type</span></code><span style="background-color: #FFFFFF"> and
</span> <code>
<span style="background-color: #FFFFFF">Path2::external_string_type</span></code><span style="background-color: #FFFFFF"> are the same type.</span></p>
<p><i><span style="background-color: #FFFFFF">Effects:</span></i><span style="background-color: #FFFFFF">
As if <code>system_error_code ec( create_hard_link( to_p, from_p ) );</code></span></p>
<p><span style="font-style: italic; background-color: #FFFFFF">Throws:</span><span style="background-color: #FFFFFF">
</span> <code>basic_filesystem_error<Path1, Path2></code><span style="background-color: #FFFFFF">
if <code>ec</code> is not zero.</span></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">template <class Path1, class Path2>
error_code create_symlink(const Path1& to_p, const Path2& from_p, error_code& ec);</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Requires:</span></i><span style="background-color: #FFFFFF">
</span> <code><span style="background-color: #FFFFFF">Path1::external_string_type</span></code><span style="background-color: #FFFFFF"> and
</span> <code>
<span style="background-color: #FFFFFF">Path2::external_string_type</span></code><span style="background-color: #FFFFFF"> are the same type.</span></p>
<p><i><span style="background-color: #FFFFFF">Effects:</span></i><span style="background-color: #FFFFFF"> Establishes the postcondition, as if by
</span> <i><span style="background-color: #FFFFFF">POSIX</span></i><span style="background-color: #FFFFFF">
</span> <code>
<span style="background-color: #FFFFFF">
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/symlink.html">
symlink()</a></span></code><span style="background-color: #FFFFFF">.</span></p>
<p><i><span style="background-color: #FFFFFF">Returns:</span></i><span style="background-color: #FFFFFF"> If the
postcondition cannot be established, a system error code
indicating the reason for the failure, otherwise 0.</span></p>
<p><span style="background-color: #FFFFFF"><i>Postcondition:</i> <code>from_p</code>
resolves to a symbolic link file that contains an unspecified representation
of <code>to_p</code>.</span></p>
<p><span style="background-color: #FFFFFF">[</span><i><span style="background-color: #FFFFFF">Note:</span></i><span style="background-color: #FFFFFF">
Some operating systems do not support symbolic links at all or support
them only for regular files. Thus symbolic links should be avoided if code portability is
a concern. </span> <i><span style="background-color: #FFFFFF">-- end note</span></i><span style="background-color: #FFFFFF">]</span></p>
</blockquote>
<pre><span style="background-color: #FFFFFF">template <class Path1, class Path2>
void create_symlink(const Path1& to_p, const Path2& from_p);</span></pre>
<blockquote>
<p><i><span style="background-color: #FFFFFF">Requires:</span></i><span style="background-color: #FFFFFF">
</span> <code><span style="background-color: #FFFFFF">Path1::external_string_type</span></code><span style="background-color: #FFFFFF"> and
</span> <code>
<span style="background-color: #FFFFFF">Path2::external_string_type</span></code><span style="background-color: #FFFFFF"> are the same type.</span></p>
<p><i><span style="background-color: #FFFFFF">Effects:</span></i><span style="background-color: #FFFFFF">
As if <code>system_error_code ec( create_symlink( to_p, from_p ) );</code></span></p>
<p><span style="font-style: italic; background-color: #FFFFFF">Throws:</span><span style="background-color: #FFFFFF">
</span> <code>basic_filesystem_error<Path1, Path2></code><span style="background-color: #FFFFFF">
if <code>ec</code> is not zero.</span></p>
</blockquote>
<pre>template <class Path> bool remove(const Path& p, system::error_code & ec = <i>singular</i> );</pre>
<blockquote>
<p><i>Effects:</i> Removes the file <code>p</code>,
as if by<i> POSIX </i><code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/remove.html">remove()</a></code>.
If no error is reported by the underlying removal implementation or if <code>
status(p).type() == file_not_found</code>, then:</p>
<ul>
<li>if <code>ec != </code><i><code>singular</code></i>, then <code>ec.clear()</code>.</li>
</ul>
<p>Otherwise,</p>
<ul>
<li>if <code>ec != </code><i><code>singular</code></i>, then set <code>ec</code>
to represent the error.</li>
<li>otherwise, throw <code>basic_filesystem_error<Path></code> to represent
the error.if <code>ec != </code><i><code>singular</code></i>, then <code>
ec.clear()</code></li>
</ul>
<p><i>Returns:</i> <code>true</code> if the file was removed, otherwise <code>
false</code>.</p>
<p><i>Postcondition:</i> <code>!exists(p)</code></p>
<p><i>Throws:</i> See <i>Effects</i>.</p>
<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>
<pre>template <class Path> unsigned long remove_all(const Path& p);</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>
<p><i>Returns:</i> The number of files removed.</p>
<p><i>Postcondition:</i> <code>!exists(p)</code></p>
<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>
<pre>template <class Path1, class Path2> void rename(const Path1& from_p, const Path2& to_p);</pre>
<blockquote>
<p><i>Requires:</i> <code>Path1::external_string_type</code> and <code>
Path2::external_string_type</code> are the same type. </p>
<p><i>Effects:</i> Renames <code>from_p</code> to <code>to_p</code>, as if by
<i>POSIX</i> <code>
<a href="http://www.opengroup.org/onlinepubs/000095399/functions/rename.html">
rename()</a></code>.</p>
<p><i>Postconditions:</i> <code>!exists(from_p) && exists(to_p)</code>, and
the contents and attributes of the file originally named <code>from_p</code>
are otherwise unchanged.</p>
<p>[<i>Note:</i> If <code>from_p</code> and <code>to_p</code> resolve to the
same file, no action is taken. Otherwise, if <code>to_p</code> resolves to an
existing file, it is removed. A symbolic link is itself renamed, rather than
the file it resolves to being renamed. <i>-- end note</i>]</p>
</blockquote>
<pre>template <class Path1, class Path2>
void copy_file(const Path1& from_fp, const Path2& to_fp,
BOOST_SCOPED_ENUM(copy_option) option=<a href="#copy_option">copy_option</a>::fail_if_exists);</pre>
<blockquote>
<p><i>Requires:</i> <code>Path1::external_string_type</code> and <code>
Path2::external_string_type</code> are the same type. </p>
<p><i>Effects:</i> The contents and attributes of the file <code>from_fp</code>
resolves to are copied to the file <code>to_fp</code> resolves to.</p>
<p><i>Throws:</i> <code>basic_filesystem_error<Path></code> if <code>
from_fp.empty() || to_fp.empty() ||!exists(from_fp) || !is_regular_file(from_fp)
|| (option==<a href="#copy_option">copy_option</a>::fail_if_exists && exists(to_fp))</code></p>
</blockquote>
<pre>template <class Path> Path complete(const Path& p, const Path& base=initial_path<Path>());</pre>
<blockquote>
<p><i>Effects:</i> Composes a complete path from <code>p</code> and <code>base</code>,
using the following rules:</p>
<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111">
<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>p</code></td>
<td align="center">precondition failure</td>
</tr>
<tr>
<td align="center"><b><code>!p.has_root_name()</code></b></td>
<td align="center"><code>base.root_name()<br>
/ p</code></td>
<td align="center"><code>base / p</code></td>
</tr>
</table>
<p><i>Returns:</i> The composed path.</p>
<p><i>Postcondition:</i> For the returned path, <code>rp,</code> <code>
rp.is_complete()</code> is true.</p>
<p><i>Throws:</i>
<span style="background-color: #FFFFFF">If </span> <code>
<span style="background-color: #FFFFFF">!(base.is_complete() && (p.is_complete() || !p.has_root_name()))</span></code></p>
<p>[<i><a name="complete_note">Note</a>:</i> When portable behavior is
required, use <i>complete()</i>. When operating system dependent behavior is
required, use <i>system_complete()</i>.</p>
<p>Portable behavior is useful when dealing with paths created
internally within a program, particularly if the program should exhibit the
same behavior on all operating systems.</p>
<p>Operating system dependent behavior is useful when dealing with
paths supplied by user input, reported to program users, or when such behavior
is expected by program users. <i>--
end note</i>]</p>
</blockquote>
<pre>template <class Path> Path system_complete(const Path& p);</pre>
<blockquote>
<p><i>Effects:</i> Composes a complete 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_complete()</code> is true.</p>
<p><i>Throws:</i> <span style="background-color: #FFFFFF">If <code>p.empty()</code>.</span></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_complete() || !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>
<h4><a name="Convenience-functions">Convenience functions</a></h4>
<pre>template <class Path> bool create_directories(const Path & p);</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>Returns:</i> The value of <code>!exists(p)</code> prior to the
establishment of the postcondition.</p>
<p><i>Postcondition:</i> <code>is_directory(p)</code></p>
<p><i>Throws:</i> <code>basic_filesystem_error<Path></code> if<code>
exists(p) && !is_directory(p)</code></p>
</blockquote>
<table border="1" cellpadding="5" cellspacing="1" style="border-collapse: collapse" bordercolor="#111111">
<tr>
<td>
<h4>Deprecated convenience functions</h4>
<p>The following functions have been replaced by <code>basic_path</code>
member functions <code>extension()</code>, <code>stem()</code>, and <code>
replace_extension()</code>.</p>
<pre>template <class Path> typename Path::string_type extension(const Path & p);</pre>
<blockquote>
<p><i>Returns:</i> if <code>p.filename()</code> contains a <i>dot</i>, returns
the substring of <code>p.filename()</code> starting at the rightmost <i>dot</i>
and ending at the string's end. Otherwise, returns an empty string. </p>
<p>[<i>Note:<b> </b></i>The <i>dot</i> is included in the return value so that
it is possible to distinguish between no extension and an empty extension. </p>
<p>Implementations are permitted but not required to define additional
behavior for file systems which append additional elements to extensions, such
as alternate data stream or partitioned dataset names. <i>-- end note</i>]</p>
</blockquote>
<pre>template <class Path> typename Path::string_type basename(const Path & p);</pre>
<blockquote>
<p><i>Returns:</i> if <code>p.filename()</code> contains a <i>dot</i>, returns
the substring of <code>p.filename()</code> starting at its beginning and
ending at the last <i>dot</i> (the <i>dot</i> is not included). Otherwise,
returns <code>
p.filename()</code>.</p>
</blockquote>
<pre>template <class Path>
Path change_extension(const Path & p, const typename Path::string_type & new_extension);</pre>
<blockquote>
<p><i>Postcondition:</i> <code>basename(<i>return_value</i>) == basename(p) &&
extension(<i>return_value</i>) == new_extension</code> </p>
<p>[<i>Note:</i> It follows from the semantics of <code>extension()</code>
that <code>new_extension</code> should include <i>dot</i> to achieve
reasonable results. <i>-- end note</i>]</p>
</blockquote>
</td>
</tr>
</table>
<h3><a name="header-fstream">Additions</a> to header <code><fstream></code></h3>
<blockquote>
<p><span style="background-color: #E0E0E0; font-style:italic">These additions have been carefully
specified to avoid breaking existing code in common operating environments such as
</span> <i><span style="background-color: #E0E0E0">POSIX</span></i><span style="background-color: #E0E0E0; font-style:italic">,
</span> <i>
<span style="background-color: #E0E0E0">Windows</span></i><span style="background-color: #E0E0E0; font-style:italic">, and
</span> <i><span style="background-color: #E0E0E0">OpenVMS.
See </span><a href="#Suggestions-for-fstream">
<span style="background-color: #E0E0E0">Suggestions for <code><fstream></code>
implementations</span></a><span style="background-color: #E0E0E0"> for
techniques to avoid breaking existing code in other environments, particularly
on operating systems allowing slashes in filenames.</span></i></p>
<p><span style="background-color: #FFFFFF">[<i>Note:</i> The
"do-the-right-thing" rule from <a href="#Requirements-on-implementations">
Requirements on implementations</a> does apply to header <code><fstream></code>.</span></p>
<p><span style="background-color: #FFFFFF">The overloads
below are specified as additions rather than replacements for existing
functions. This preserves existing code (perhaps
using a <a name="home-grown-path">home-grown path</a> class) that relies on an
automatic conversion to <code>const char*</code>.<i> -- end note</i>]</span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>In 27.8.1.1 Class template
basic_filebuf [lib.filebuf] synopsis preceding paragraph 1, add the function:</i></span></p>
<blockquote>
<pre><span style="background-color: #FFFFFF">template <class Path> </span><span style="background-color: #FFFFFF">basic_filebuf</span><span style="background-color: #FFFFFF"><charT,traits>* </span><span style="background-color: #FFFFFF">open(const</span><span style="background-color: #FFFFFF"> Path& p, </span><span style="background-color: #FFFFFF">ios_base::openmode</span><span style="background-color: #FFFFFF"> mode);</span></pre>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>In 27.8.1.3 Member functions [lib.filebuf.members],
add the above to the signature preceding paragraph 2, and replace the
sentence:</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF">It then opens a file, if possible,
whose name is the NTBS s (“as if†by calling <code>std::fopen(s ,<i>modstr</i>
))</code>.</span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>with:</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF">It then opens, if possible, the file
that
<code>p</code> or <code>path(s)</code> resolves to, “as if†by calling <code>std::fopen()</code> with a
second argument of <i>modstr</i>.</span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>In 27.8.1.5 Class template
basic_ifstream [lib.ifstream] synopsis preceding paragraph 1, add the functions:</i></span></p>
<blockquote>
<pre><span style="background-color: #FFFFFF">template <class Path> explicit basic_ifstream(const Path& p, ios_base::openmode mode = ios_base::in);
template <class Path> void open(const Path& p, ios_base::openmode mode = ios_base::in);</span></pre>
</blockquote>
<p><i><span style="background-color: #FFFFFF">In 27.8.1.6 basic_ifstream
constructors [lib.ifstream.cons] </span></i>
<span style="background-color: #FFFFFF"><i>add the above constructor to the signature preceding
paragraph 2, and in paragraph 2 replace</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(s, mode |
ios_base::in)</code></span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>with</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(path(s), mode |
ios_base::in)</code> or <code>rdbuf()->open(p, mode | ios_base::in)</code> as
appropriate</span></p>
</blockquote>
<p><i><span style="background-color: #FFFFFF">In 27.8.1.7 Member functions [lib.ifstream.members]
</span></i><span style="background-color: #FFFFFF"><i>add the above open
function to the signature
preceding paragraph 3, and in paragraph 3 replace</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(s, mode |
ios_base::in)</code></span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>with</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(path(s), mode |
ios_base::in)</code> or <code>rdbuf()->open(p, mode | ios_base::in)</code> as
appropriate</span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>In 27.8.1.8 Class template
basic_ofstream [lib.ofstream] synopsis preceding paragraph 1, add the
functions:</i></span></p>
<blockquote>
<pre><span style="background-color: #FFFFFF">template <class Path> explicit basic_ofstream(const Path& p, ios_base::openmode mode = ios_base::out);
template <class Path> void open(const Path& p, ios_base::openmode mode = ios_base::out);</span></pre>
</blockquote>
<p><i><span style="background-color: #FFFFFF">In 27.8.1.9 basic_ofstream
constructors [lib.ofstream.cons] </span></i>
<span style="background-color: #FFFFFF"><i>add the above constructor to the signature preceding
paragraph 2, and in paragraph 2 replace</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(s, mode |
ios_base::out)</code></span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>with</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(path(s), mode |
ios_base::out)</code> or <code>rdbuf()->open(p, mode | ios_base::out)</code> as
appropriate</span></p>
</blockquote>
<p><i><span style="background-color: #FFFFFF">In 27.8.1.10 Member functions [lib.ofstream.members]
</span></i><span style="background-color: #FFFFFF"><i>add the above open
function to the signature
preceding paragraph 3, and in paragraph 3 replace</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(s, mode |
ios_base::out)</code></span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>with</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(path(s), mode |
ios_base::out)</code> or <code>rdbuf()->open(p, mode | ios_base::out)</code> as
appropriate</span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>In 27.8.1.11 Class template
basic_fstream [lib.fstream] synopsis preceding paragraph 1, add the functions:</i></span></p>
<blockquote>
<pre><span style="background-color: #FFFFFF">template <class Path> explicit basic_fstream(const Path& p, ios_base::openmode mode = ios_base::in|ios_base::out);
template <class Path> void open(const Path& p, ios_base::openmode mode = ios_base::in|ios_base::out);</span></pre>
</blockquote>
<p><i><span style="background-color: #FFFFFF">In 27.8.1.12 basic_fstream
constructors [lib.fstream.cons] </span></i>
<span style="background-color: #FFFFFF"><i>add the above constructor to the signature preceding
paragraph 2, and in paragraph 2 replace</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(s, mode)</code></span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>with</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(path(s), mode)</code>
or <code>rdbuf()->open(p, mode)</code> as appropriate</span></p>
</blockquote>
<p><i><span style="background-color: #FFFFFF">In 27.8.1.13 Member functions [lib.fstream.members]
</span></i><span style="background-color: #FFFFFF"><i>add the above open
function to the signature
preceding paragraph 3, and in paragraph 3 replace</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(s, mode)</code></span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>with</i></span></p>
<blockquote>
<p><span style="background-color: #FFFFFF"><code>rdbuf()->open(path(s), mode)</code>
or <code>rdbuf()->open(p, mode)</code> as appropriate</span></p>
</blockquote>
<p><span style="background-color: #FFFFFF"><i>End of proposed text.</i></span></p>
<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" width="1066">
<p>
<tr><td width="112"><b>Constructor<br>argument</b></td>
<td width="160"><b>Elements found<br>by iteration</b></td>
<td width="112"><b><code>string()</code></b></td>
<td width="112"><code><b>file_<br>string()</b></td>
<td width="72"><b><code>root_<br>path()<br>.string()</code></b></td>
<td width="48"><b><code>root_<br>name()</code></b></td>
<td width="88"><b><code>root_<br>directory()</code></b></td>
<td width="96"><b><code>relative_<br>path()<br>.string()</code></b></td>
<td width="72"><b><code>parent_<br>path()<br>.string()</code></b></td>
<td width="72"><b><code>filename()</code></b></td>
</tr>
<tr>
<td width="112"><code>""</code></td>
<td width="160"><code>""</code></td>
<td width="112"><code>""</code></td>
<td width="112"><code>""</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>""</code></td>
<td width="72"><code>""</code></td>
<td width="72"><code>""</code></td>
</tr>
<tr>
<td width="112"><code>"."</code></td>
<td width="160"><code>"."</code></td>
<td width="112"><code>"."</code></td>
<td width="112"><code>"."</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"."</code></td>
<td width="72"><code>""</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>".."</code></td>
<td width="160"><code>".."</code></td>
<td width="112"><code>".."</code></td>
<td width="112"><code>".."</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>".."</code></td>
<td width="72"><code>""</code></td>
<td width="72"><code>".."</code></td>
</tr>
<tr>
<td width="112"><code>"foo"</code></td>
<td width="160"><code>"foo"</code></td>
<td width="112"><code>"foo"</code></td>
<td width="112"><code>"foo"</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"foo"</code></td>
<td width="72"><code>""</code></td>
<td width="72"><code>"foo"</code></td>
</tr>
<tr>
<td width="112"><code>"/"</code></td>
<td width="160"><code>"/"</code></td>
<td width="112"><code>"/"</code></td>
<td bgcolor="#99FF66" width="112"><code>"/"<br>"\"</code></td>
<td width="72"><code>"/"</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>"/"</code></td>
<td width="96"><code>""</code></td>
<td width="72"><code>""</code></td>
<td width="72"><code>"/"</code></td>
</tr>
<tr>
<td width="112"><code>"/foo"</code></td>
<td width="160"><code>"/","foo"</code></td>
<td width="112"><code>"/foo"</code></td>
<td bgcolor="#99FF66" width="112"><code>"/foo"<br>"\foo"</code></td>
<td width="72"><code>"/"</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>"/"</code></td>
<td width="96"><code>"foo"</code></td>
<td width="72"><code>"/"</code></td>
<td width="72"><code>"foo"</code></td>
</tr>
<tr>
<td width="112"><code>"foo/"</code></td>
<td width="160"><code>"foo","."</code></td>
<td width="112"><code>"foo/"</code></td>
<td bgcolor="#99FF66" width="112"><code>"foo/"<br>"foo\"</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"foo/"</code></td>
<td width="72"><code>"foo"</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"/foo/"</code></td>
<td width="160"><code>"/","foo","."</code></td>
<td width="112"><code>"/foo/"</code></td>
<td bgcolor="#99FF66" width="112"><code>"/foo/"<br>"\foo\"</code></td>
<td width="72"><code>"/"</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>"/"</code></td>
<td width="96"><code>"foo/"</code></td>
<td width="72"><code>"/foo"</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"foo/bar"</code></td>
<td width="160"><code>"foo","bar"</code></td>
<td width="112"><code>"foo/bar"</code></td>
<td bgcolor="#99FF66" width="112"><code>"foo/bar"<br>"foo\bar"</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"foo/bar"</code></td>
<td width="72"><code>"foo"</code></td>
<td width="72"><code>"bar"</code></td>
</tr>
<tr>
<td width="112"><code>"/foo/bar"</code></td>
<td width="160"><code>"/","foo","bar"</code></td>
<td width="112"><code>"/foo/bar"</code></td>
<td bgcolor="#99FF66" width="112"><code>"/foo/bar"<br>"\foo\bar"</code></td>
<td width="72"><code>"/"</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>"/"</code></td>
<td width="96"><code>"foo/bar"</code></td>
<td width="72"><code>"/foo"</code></td>
<td width="72"><code>"bar"</code></td>
</tr>
<tr>
<td width="112"><code>"///foo///"</code></td>
<td width="160"><code>"/","foo","."</code></td>
<td width="112"><code>"///foo///"</code></td>
<td bgcolor="#99FF66" width="112"><code>"///foo///"<br>"\foo\\\"</code></td>
<td width="72"><code>"/"</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>"/"</code></td>
<td width="96"><code>"foo///"</code></td>
<td width="72"><code>"///foo"</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"///foo///bar"</code></td>
<td width="160"><code>"/","foo","bar"</code></td>
<td width="112"><code>"///foo///bar"</code></td>
<td bgcolor="#99FF66" width="112"><code>"///foo///bar"<br>"\foo\\\bar"</code></td>
<td width="72"><code>"/"</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>"/"</code></td>
<td width="96"><code>"foo///bar"</code></td>
<td width="72"><code>"///foo"</code></td>
<td width="72"><code>"bar"</code></td>
</tr>
<tr>
<td width="112"><code>"/."</code></td>
<td width="160"><code>"/","."</code></td>
<td width="112"><code>"/."</code></td>
<td bgcolor="#99FF66" width="112"><code>"/."<br>"\."</code></td>
<td width="72"><code>"/"</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>"/"</code></td>
<td width="96"><code>"."</code></td>
<td width="72"><code>"/"</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"./"</code></td>
<td width="160"><code>".","."</code></td>
<td width="112"><code>"./"</code></td>
<td bgcolor="#99FF66" width="112"><code>"./"<br>".\"</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"./"</code></td>
<td width="72"><code>"."</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"/.."</code></td>
<td width="160"><code>"/",".."</code></td>
<td width="112"><code>"/.."</code></td>
<td bgcolor="#99FF66" width="112"><code>"/.."<br>"\.."</code></td>
<td width="72"><code>"/"</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>"/"</code></td>
<td width="96"><code>".."</code></td>
<td width="72"><code>"/"</code></td>
<td width="72"><code>".."</code></td>
</tr>
<tr>
<td width="112"><code>"../"</code></td>
<td width="160"><code>"..","."</code></td>
<td width="112"><code>"../"</code></td>
<td bgcolor="#99FF66" width="112"><code>"../"<br>"..\"</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"../"</code></td>
<td width="72"><code>".."</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"foo/."</code></td>
<td width="160"><code>"foo","."</code></td>
<td width="112"><code>"foo/."</code></td>
<td bgcolor="#99FF66" width="112"><code>"foo/."<br>"foo\."</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"foo/."</code></td>
<td width="72"><code>"foo"</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"foo/.."</code></td>
<td width="160"><code>"foo",".."</code></td>
<td width="112"><code>"foo/.."</code></td>
<td bgcolor="#99FF66" width="112"><code>"foo/.."<br>"foo\.."</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"foo/.."</code></td>
<td width="72"><code>"foo"</code></td>
<td width="72"><code>".."</code></td>
</tr>
<tr>
<td width="112"><code>"foo/./"</code></td>
<td width="160"><code>"foo",".","."</code></td>
<td width="112"><code>"foo/./"</code></td>
<td bgcolor="#99FF66" width="112"><code>"foo/./"<br>"foo\.\"</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"foo/./"</code></td>
<td width="72"><code>"foo/."</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"foo/./bar"</code></td>
<td width="160"><code>"foo",".","bar"</code></td>
<td width="112"><code>"foo/./bar"</code></td>
<td bgcolor="#99FF66" width="112"><code>"foo/./bar"<br>"foo\.\bar"</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"foo/./bar"</code></td>
<td width="72"><code>"foo/."</code></td>
<td width="72"><code>"bar"</code></td>
</tr>
<tr>
<td width="112"><code>"foo/.."</code></td>
<td width="160"><code>"foo",".."</code></td>
<td width="112"><code>"foo/.."</code></td>
<td bgcolor="#99FF66" width="112"><code>"foo/.."<br>"foo\.."</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"foo/.."</code></td>
<td width="72"><code>"foo"</code></td>
<td width="72"><code>".."</code></td>
</tr>
<tr>
<td width="112"><code>"foo/../"</code></td>
<td width="160"><code>"foo","..","."</code></td>
<td width="112"><code>"foo/../"</code></td>
<td bgcolor="#99FF66" width="112"><code>"foo/../"<br>"foo\..\"</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"foo/../"</code></td>
<td width="72"><code>"foo/.."</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"foo/../bar"</code></td>
<td width="160"><code>"foo","..","bar"</code></td>
<td width="112"><code>"foo/../bar"</code></td>
<td bgcolor="#99FF66" width="112"><code>"foo/../bar"<br>"foo\..\bar"</code></td>
<td width="72"><code>""</code></td>
<td width="48"><code>""</code></td>
<td width="88"><code>""</code></td>
<td width="96"><code>"foo/../bar"</code></td>
<td width="72"><code>"foo/.."</code></td>
<td width="72"><code>"bar"</code></td>
</tr>
<tr>
<td width="112"><code>"c:"</code></td>
<td width="160"><code>"c:"</code></td>
<td width="112"><code>"c:"</code></td>
<td width="112"><code>"c:"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1; border-top-style: solid; border-top-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td width="88"><code>""</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:"<br>""</code></td>
<td width="72"><code>""</code></td>
<td width="72"><code>"c:"</code></td>
</tr>
<tr>
<td width="112"><code>"c:/"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:","."<br>"c:","/"</code></td>
<td width="112"><code>"c:/"</code></td>
<td bgcolor="#99FF66" width="112"><code><span style="background-color: #99FF66">
"c:/"<br>"c:\"</span></code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="88"><code>""<br>"/"</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:/"<br>""</code></td>
<td width="72"><code>"c:"</code></td>
<td bgcolor="#99FF66" width="72"><code>"."<br>"/"</code></td>
</tr>
<tr>
<td width="112"><code>"c:foo"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:foo"<br>"c:","foo"</code></td>
<td width="112"><code>"c:foo"</code></td>
<td width="112"><code>"c:foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td width="88"><code>""</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:foo"<br>"foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="72"><code>"c:foo"<br>"foo"</code></td>
</tr>
<tr>
<td width="112"><code>"c:/foo"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:","foo"<br>"c:","/","foo"</code></td>
<td width="112"><code>"c:/foo"</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:/foo"<br>"c:\foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="88"><code>""<br>"/"</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:/foo"<br>"foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>"c:"<br>"c:/"</code></td>
<td width="72"><code>"foo"</code></td>
</tr>
<tr>
<td width="112"><code>"c:foo/"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:foo","."<br>"c:","foo","."</code></td>
<td width="112"><code>"c:foo/"</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:foo/"<br>"c:foo\"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td width="88"><code>""</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:foo/"<br>"foo/"</code></td>
<td width="72"><code>"c:foo"</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"c:/foo/"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:","foo","."<br>"c:","/","foo","."</code></td>
<td width="112"><code>"c:/foo/"</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:/foo/"<br>"c:\foo\"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="88"><code>""<br>"/"</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:/foo/"<br>"foo/"</code></td>
<td width="72"><code>"c:/foo"</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"c:/foo/bar"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:","foo","bar"<br>"c:","/","foo","bar"</code></td>
<td width="112"><code>"c:/foo/bar"</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:/foo/bar"<br>"c:\foo\bar"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="88"><code>""<br>"/"</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:/foo/bar"<br>"foo/bar"</code></td>
<td width="72"><code>"c:/foo"</code></td>
<td width="72"><code>"bar"</code></td>
</tr>
<tr>
<td width="112"><code>"prn:"</code></td>
<td width="160"><code>"prn:"</code></td>
<td width="112"><code>"prn:"</code></td>
<td width="112"><code>"prn:"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"prn:"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"prn:"</code></td>
<td width="88"><code>""</code></td>
<td bgcolor="#99FF66" width="96"><code>"prn:"<br>""</code></td>
<td width="72"><code>""</code></td>
<td width="72"><code>"prn:"</code></td>
</tr>
<tr>
<td width="112"><code>"c:\"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:\"<br>"c:","/"</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:\"<br>"c:/"</code></td>
<td width="112"><code>"c:\"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="88"><code>""<br>"/"</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:\"<br>""</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="72"><code>"c:\"<br>"/"</code></td>
</tr>
<tr>
<td width="112"><code>"c:foo"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:foo"<br>"c:","foo"</code></td>
<td width="112"><code>"c:foo"</code></td>
<td width="112"><code>"c:foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td width="88"><code>""</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:foo"<br>"foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="72"><code>"c:foo"<br>"foo"</code></td>
</tr>
<tr>
<td width="112"><code>"c:\foo"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:\foo"<br>"c:","/","foo"</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:\foo"<br>"c:/foo"</code></td>
<td width="112"><code>"c:\foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="88"><code>""<br>"/"</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:\foo"<br>"foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/"</code></td>
<td bgcolor="#99FF66" width="72"><code>"c:\foo"<br>"foo"</code></td>
</tr>
<tr>
<td width="112"><code>"c:foo\"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:foo\"<br>"c:","foo","."</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:foo\"<br>"c:foo/"</code></td>
<td width="112"><code>"c:foo\"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td width="88"><code>""</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:foo\"<br>"foo/"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>"c:foo\"<br>"."</code></td>
</tr>
<tr>
<td width="112"><code>"c:\foo\"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:\foo\"<br>"c:","/","foo","."</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:\foo\"<br>"c:/foo/"</code></td>
<td width="112"><code>"c:\foo\"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="88"><code>""<br>"/"</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:\foo\"<br>"foo/"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>"c:\foo\"<br>"."</code></td>
</tr>
<tr>
<td width="112"><code>"c:\foo/"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:\foo","."<br>"c:","/","foo","."</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:\foo/"<br>"c:/foo/"</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:\foo/"<br>"c:\foo\"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="88"><code>""<br>"/"</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:\foo/"<br>"foo/"</code></td>
<td bgcolor="#99FF66" width="72"><code>"c:\foo"<br>"c:/foo"</code></td>
<td width="72"><code>"."</code></td>
</tr>
<tr>
<td width="112"><code>"c:/foo\bar"</code></td>
<td bgcolor="#99FF66" width="160"><code>"c:","foo\bar"<br>"c:","/","foo","bar"</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:/foo\bar"<br>"c:/foo/bar"</code></td>
<td bgcolor="#99FF66" width="112"><code>"c:/foo\bar"<br>"c:\foo\bar"</code></td>
<td bgcolor="#99FF66" width="72"><code>""<br>"c:/"</code></td>
<td bgcolor="#99FF66" style="border-left-style: solid; border-left-width: 1; border-right-style: solid; border-right-width: 1; border-bottom-style: solid; border-bottom-width: 1" width="48"><code>
""<br>"c:"</code></td>
<td bgcolor="#99FF66" width="88"><code>""<br>"/"</code></td>
<td bgcolor="#99FF66" width="96"><code>"c:/foo\bar"<br>"foo/bar"</code></td>
<td bgcolor="#99FF66" width="72"><code>"c:"<br>"c:/foo"</code></td>
<td bgcolor="#99FF66" width="72"><code>"foo\bar"<br>"bar"</code></td>
</tr>
</table>
<h2><a name="Suggestions-for-fstream">Suggestions for <code><fstream></code></a>
implementations</h2>
<p><span style="background-color: #FFFFFF">The change in semantics to functions
taking <code>const char*</code> arguments can break existing code, but only on
operating systems where implementations don't
<a href="#Pathname-formats">implicitly accept native format pathnames</a> or
operating systems that allow slashes in filenames. Thus on <i>POSIX</i>,
<i>Windows,</i> and <i>OpenVMS</i>, for example, there is no problem if the
implementation follows encouraged behavior.</span></p>
<p><span style="background-color: #FFFFFF">For most of the Filesystem Library,
there is no existing code, so the issue preserving existing code that uses
slashes in filenames doesn't arise. New code simply must use basic_path
constructors with <code>path_format_t</code> arguments of <code>native</code>.
To preserve existing fstream code that uses slashes in filenames, an
implementation may wish to provide a mechanism such as a macro to control
selection of the old behavior.</span></p>
<p><span style="background-color: #FFFFFF">Implementations are already required
by the TR front-matter to provide a mechanism such as a macro to control
selection of the old behavior (useful to guarantee protection of existing code)
or new behavior (useful in new code, and code being ported from other systems)
for headers. Because use of the rest of the Filesystem Library is independent of
use of the <code><fstream></code> additions, affected implementations are
encouraged to allow disabling the <code><fstream></code> additions separately
from other TR features.</span></p>
<p><span style="background-color: #FFFFFF">An rejected alternative was to supply
new fstream classes in namespace <code>filesystem</code>, inheriting from the current
classes, overriding the constructors and opens taking pathname arguments, and
providing the additional overloads. In Lillehammer LWG members indicated lack of
support for this alternative, feeling that costs outweigh benefits.</span></p>
<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.</p>
<p>Howard Hinnant and John Maddock reviewed a draft of the proposal, and
identified a number of mistakes or weaknesses, resulting in a more polished
final document.</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>
<hr>
<p>© Copyright Beman Dawes, 2002, 2006, 2007</p>
<p>Distributed under the Boost Software License, Version 1.0. See
<a href="http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a></p>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B %Y" startspan -->10 November 2009<!--webbot bot="Timestamp" endspan i-checksum="40581" --></p>
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