|
398
|
1 # mmap-anon.m4 serial 8
|
|
|
2 dnl Copyright (C) 2005, 2007, 2009-2010 Free Software Foundation, Inc.
|
|
|
3 dnl This file is free software; the Free Software Foundation
|
|
|
4 dnl gives unlimited permission to copy and/or distribute it,
|
|
|
5 dnl with or without modifications, as long as this notice is preserved.
|
|
|
6
|
|
|
7 # Detect how mmap can be used to create anonymous (not file-backed) memory
|
|
|
8 # mappings.
|
|
|
9 # - On Linux, AIX, OSF/1, Solaris, Cygwin, Interix, Haiku, both MAP_ANONYMOUS
|
|
|
10 # and MAP_ANON exist and have the same value.
|
|
|
11 # - On HP-UX, only MAP_ANONYMOUS exists.
|
|
|
12 # - On MacOS X, FreeBSD, NetBSD, OpenBSD, only MAP_ANON exists.
|
|
|
13 # - On IRIX, neither exists, and a file descriptor opened to /dev/zero must be
|
|
|
14 # used.
|
|
|
15
|
|
|
16 AC_DEFUN([gl_FUNC_MMAP_ANON],
|
|
|
17 [
|
|
|
18 dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
|
|
|
19 AC_REQUIRE([AC_PROG_CPP])
|
|
|
20 AC_REQUIRE([AC_PROG_EGREP])
|
|
|
21
|
|
|
22 dnl Persuade glibc <sys/mman.h> to define MAP_ANONYMOUS.
|
|
|
23 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
|
|
|
24
|
|
|
25 # Check for mmap(). Don't use AC_FUNC_MMAP, because it checks too much: it
|
|
|
26 # fails on HP-UX 11, because MAP_FIXED mappings do not work. But this is
|
|
|
27 # irrelevant for anonymous mappings.
|
|
|
28 AC_CHECK_FUNC([mmap], [gl_have_mmap=yes], [gl_have_mmap=no])
|
|
|
29
|
|
|
30 # Try to allow MAP_ANONYMOUS.
|
|
|
31 gl_have_mmap_anonymous=no
|
|
|
32 if test $gl_have_mmap = yes; then
|
|
|
33 AC_MSG_CHECKING([for MAP_ANONYMOUS])
|
|
|
34 AC_EGREP_CPP([I cant identify this map.], [
|
|
|
35 #include <sys/mman.h>
|
|
|
36 #ifdef MAP_ANONYMOUS
|
|
|
37 I cant identify this map.
|
|
|
38 #endif
|
|
|
39 ],
|
|
|
40 [gl_have_mmap_anonymous=yes])
|
|
|
41 if test $gl_have_mmap_anonymous != yes; then
|
|
|
42 AC_EGREP_CPP([I cant identify this map.], [
|
|
|
43 #include <sys/mman.h>
|
|
|
44 #ifdef MAP_ANON
|
|
|
45 I cant identify this map.
|
|
|
46 #endif
|
|
|
47 ],
|
|
|
48 [AC_DEFINE([MAP_ANONYMOUS], [MAP_ANON],
|
|
|
49 [Define to a substitute value for mmap()'s MAP_ANONYMOUS flag.])
|
|
|
50 gl_have_mmap_anonymous=yes])
|
|
|
51 fi
|
|
|
52 AC_MSG_RESULT([$gl_have_mmap_anonymous])
|
|
|
53 if test $gl_have_mmap_anonymous = yes; then
|
|
|
54 AC_DEFINE([HAVE_MAP_ANONYMOUS], [1],
|
|
|
55 [Define to 1 if mmap()'s MAP_ANONYMOUS flag is available after including
|
|
|
56 config.h and <sys/mman.h>.])
|
|
|
57 fi
|
|
|
58 fi
|
|
|
59 ])
|
