On HP-UX 11, anonymous mmap is possible, through the MAP_ANONYMOUS flag.
But gl_FUNC_MMAP_ANON does not define HAVE_MAP_ANONYMOUS on this platform.
Why? Because HAVE_MMAP is not defined - a consequence of the strict test
in AC_FUNC_MMAP, combined with the missing support for MAP_FIXED in HP-UX.
(The AC_FUNC_MMAP test fails here:
if (data2 != mmap (data2, pagesize, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_FIXED, fd, 0L))
return 1;
)
This fixes the MAP_ANONYMOUS detection.
2009-05-12 Bruno Haible <br...@clisp.org>
Make the MAP_ANONYMOUS detection work on HP-UX 11.
* m4/mmap-anon.m4 (gl_FUNC_MMAP_ANON): Check whether mmap exists, but
not whether its fully works.
--- m4/mmap-anon.m4.orig 2009-05-13 02:27:46.000000000 +0200
+++ m4/mmap-anon.m4 2009-05-13 02:25:58.000000000 +0200
@@ -1,4 +1,4 @@
-# mmap-anon.m4 serial 6
+# mmap-anon.m4 serial 7
dnl Copyright (C) 2005, 2007, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -22,12 +22,14 @@
dnl Persuade glibc <sys/mman.h> to define MAP_ANONYMOUS.
AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
- # Check for mmap()
- AC_FUNC_MMAP
+ # 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 $ac_cv_func_mmap_fixed_mapped = yes; then
+ 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>
