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| author | Junfeng Dong <junfeng.dong@intel.com> | 2012-06-05 17:27:50 +0800 |
|---|---|---|
| committer | Junfeng Dong <junfeng.dong@intel.com> | 2012-06-05 17:27:50 +0800 |
| commit | b5e47a5b56f360f78f0e086ca4af3159dcb28e27 (patch) | |
| tree | 7df6f7ef0ec82bdabd93c5bee5f1e2e78ba36582 /m4/mmap-anon.m4 | |
| parent | 94865d2997df82fb40f0092682e090614dd98b7f (diff) | |
| download | diffutils-b5e47a5b56f360f78f0e086ca4af3159dcb28e27.tar.gz diffutils-b5e47a5b56f360f78f0e086ca4af3159dcb28e27.tar.bz2 diffutils-b5e47a5b56f360f78f0e086ca4af3159dcb28e27.zip | |
Diffstat (limited to 'm4/mmap-anon.m4')
| -rw-r--r-- | m4/mmap-anon.m4 | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/m4/mmap-anon.m4 b/m4/mmap-anon.m4 new file mode 100644 index 0000000..a6b7b9a --- /dev/null +++ b/m4/mmap-anon.m4 @@ -0,0 +1,59 @@ +# mmap-anon.m4 serial 8 +dnl Copyright (C) 2005, 2007, 2009-2010 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +# Detect how mmap can be used to create anonymous (not file-backed) memory +# mappings. +# - On Linux, AIX, OSF/1, Solaris, Cygwin, Interix, Haiku, both MAP_ANONYMOUS +# and MAP_ANON exist and have the same value. +# - On HP-UX, only MAP_ANONYMOUS exists. +# - On MacOS X, FreeBSD, NetBSD, OpenBSD, only MAP_ANON exists. +# - On IRIX, neither exists, and a file descriptor opened to /dev/zero must be +# used. + +AC_DEFUN([gl_FUNC_MMAP_ANON], +[ + dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57. + AC_REQUIRE([AC_PROG_CPP]) + AC_REQUIRE([AC_PROG_EGREP]) + + dnl Persuade glibc <sys/mman.h> to define MAP_ANONYMOUS. + AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + + # Check for mmap(). Don't use AC_FUNC_MMAP, because it checks too much: it + # fails on HP-UX 11, because MAP_FIXED mappings do not work. But this is + # irrelevant for anonymous mappings. + AC_CHECK_FUNC([mmap], [gl_have_mmap=yes], [gl_have_mmap=no]) + + # Try to allow MAP_ANONYMOUS. + gl_have_mmap_anonymous=no + if test $gl_have_mmap = yes; then + AC_MSG_CHECKING([for MAP_ANONYMOUS]) + AC_EGREP_CPP([I cant identify this map.], [ +#include <sys/mman.h> +#ifdef MAP_ANONYMOUS + I cant identify this map. +#endif +], + [gl_have_mmap_anonymous=yes]) + if test $gl_have_mmap_anonymous != yes; then + AC_EGREP_CPP([I cant identify this map.], [ +#include <sys/mman.h> +#ifdef MAP_ANON + I cant identify this map. +#endif +], + [AC_DEFINE([MAP_ANONYMOUS], [MAP_ANON], + [Define to a substitute value for mmap()'s MAP_ANONYMOUS flag.]) + gl_have_mmap_anonymous=yes]) + fi + AC_MSG_RESULT([$gl_have_mmap_anonymous]) + if test $gl_have_mmap_anonymous = yes; then + AC_DEFINE([HAVE_MAP_ANONYMOUS], [1], + [Define to 1 if mmap()'s MAP_ANONYMOUS flag is available after including + config.h and <sys/mman.h>.]) + fi + fi +]) |