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view m4/mmap-anon.m4 @ 424:6d87423a979b 3.0-beta2
Added tag 3.0-beta2 for changeset 079d43b6967b
author | lost@l-w.ca |
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date | Sun, 19 Sep 2010 01:55:26 -0600 |
parents | 3c2e1f24cc7d |
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# 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 ])