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llvm-6502/autoconf/m4/func_mmap_file.m4

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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
])