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Diffstat (limited to 'Build/source/libs/zziplib/zziplib-0.13.58/m4/acx_restrict.m4')
| -rw-r--r-- | Build/source/libs/zziplib/zziplib-0.13.58/m4/acx_restrict.m4 | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/Build/source/libs/zziplib/zziplib-0.13.58/m4/acx_restrict.m4 b/Build/source/libs/zziplib/zziplib-0.13.58/m4/acx_restrict.m4 new file mode 100644 index 00000000000..333f2592df4 --- /dev/null +++ b/Build/source/libs/zziplib/zziplib-0.13.58/m4/acx_restrict.m4 @@ -0,0 +1,32 @@ +dnl @synopsis ACX_C_RESTRICT +dnl +dnl This macro determines whether the C compiler supports the "restrict" +dnl keyword introduced in ANSI C99, or an equivalent. Does nothing if +dnl the compiler accepts the keyword. Otherwise, if the compiler supports +dnl an equivalent (like gcc's __restrict__) defines "restrict" to be that. +dnl Otherwise, defines "restrict" to be empty. +dnl +dnl @version $Id: acx_restrict.m4,v 1.1 2005/12/09 07:47:34 guidod Exp $ +dnl @author Steven G. Johnson <stevenj@alum.mit.edu> + +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 +]) |