| # mmap-anon.m4 serial 10 |
| dnl Copyright (C) 2005, 2007, 2009-2012 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 Mac OS 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 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 cannot identify this map], [ |
| #include <sys/mman.h> |
| #ifdef MAP_ANONYMOUS |
| I cannot identify this map |
| #endif |
| ], |
| [gl_have_mmap_anonymous=yes]) |
| if test $gl_have_mmap_anonymous != yes; then |
| AC_EGREP_CPP([I cannot identify this map], [ |
| #include <sys/mman.h> |
| #ifdef MAP_ANON |
| I cannot identify this map |
| #endif |
| ], |
| [AC_DEFINE([MAP_ANONYMOUS], [MAP_ANON], |
| [Define to a substitute value for mmap()'s MAP_ANONYMOUS flag.]) |
| gl_have_mmap_anonymous=yes]) |
| fi |
| AC_MSG_RESULT([$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 |
| ]) |
