llvm-mirror/autoconf/m4/func_mmap_file.m4
Reid Spencer c90eff97f7 Fix the program passed to AC_LANG_PROGRAM to be only the BODY of the main
function, not the whole main function. This problem resulted during
conversion of scripts to the new autoconf standard. The effect was that
the mmap_file test would fail and if it does there is currently an
#ifdef'd #error that causes compilation to fail. Bad, bad, bad.

llvm-svn: 16462
2004-09-21 17:10:52 +00:00

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#
# Check for the ability to mmap a file.
#
AC_DEFUN([AC_FUNC_MMAP_FILE],
[AC_CACHE_CHECK(for mmap of files,
ac_cv_func_mmap_file,
[ AC_LANG_PUSH([C])
AC_RUN_IFELSE([
AC_LANG_PROGRAM([[
#include <sys/types.h>
#include <sys/mman.h>
#include <fcntl.h>
]],[[
int fd;
fd = creat ("foo",0777);
fd = (int) mmap (0, 1, PROT_READ, MAP_SHARED, fd, 0);
unlink ("foo");
return (fd != (int) MAP_FAILED);]])],
[ac_cv_func_mmap_file=yes],[ac_cv_func_mmap_file=no],[ac_cv_func_mmap_file=no])
AC_LANG_POP([C])
])
if test "$ac_cv_func_mmap_file" = yes; then
AC_DEFINE([HAVE_MMAP_FILE],[],[Define if mmap() can map files into memory])
AC_SUBST(MMAP_FILE,[yes])
fi
])