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| author | Jim Meyering <jim@meyering.net> | 2003-02-12 08:54:20 +0000 |
|---|---|---|
| committer | Jim Meyering <jim@meyering.net> | 2003-02-12 08:54:20 +0000 |
| commit | ac3db7d31983bdb197f1acd8b6a00b39434ccf78 (patch) | |
| tree | 6ff73071f7916c2c8e672f4c6e537cbdcd3437b4 | |
| parent | 17cef92ec069d0def7ac8ca378e37a707b406e3b (diff) | |
| download | coreutils-ac3db7d31983bdb197f1acd8b6a00b39434ccf78.tar.xz | |
verbatim from the URL in the comment
| -rw-r--r-- | m4/restrict.m4 | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/m4/restrict.m4 b/m4/restrict.m4 new file mode 100644 index 000000000..c5492f9ba --- /dev/null +++ b/m4/restrict.m4 @@ -0,0 +1,24 @@ +dnl Available from the GNU Autoconf Macro Archive at: +dnl http://www.gnu.org/software/ac-archive/htmldoc/acx_restrict.html +dnl +AC_DEFUN([ACX_C_RESTRICT], +[AC_CACHE_CHECK([for C restrict keyword], acx_cv_c_restrict, +[acx_cv_c_restrict=unsupported + AC_LANG_SAVE + AC_LANG_C + # Try the official restrict keyword, then gcc's __restrict__, then + # SGI's __restrict. __restrict has slightly different semantics than + # restrict (it's a bit stronger, in that __restrict pointers can't + # overlap even with non __restrict pointers), but I think it should be + # okay under the circumstances where restrict is normally used. + for acx_kw in restrict __restrict__ __restrict; do + AC_TRY_COMPILE([], [float * $acx_kw x;], [acx_cv_c_restrict=$acx_kw; break]) + done + AC_LANG_RESTORE +]) + if test "$acx_cv_c_restrict" != "restrict"; then + acx_kw="$acx_cv_c_restrict" + if test "$acx_kw" = unsupported; then acx_kw=""; fi + AC_DEFINE_UNQUOTED(restrict, $acx_kw, [Define to equivalent of C99 restrict keyword, or to nothing if this is not supported. Do not define if restrict is supported directly.]) + fi +]) |