diff options
Diffstat (limited to 'm4/nx-macros.m4')
| -rw-r--r-- | m4/nx-macros.m4 | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/m4/nx-macros.m4 b/m4/nx-macros.m4 index 61acfb58a..b40f628b0 100644 --- a/m4/nx-macros.m4 +++ b/m4/nx-macros.m4 @@ -304,6 +304,53 @@ m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])], [AC_SUBST([AM_DEFAULT_VERBOSITY], [1])]) ]) # NX_DEFAULT_OPTIONS +# NX_CHECK_MALLOC_ZERO +# ---------------------- +# Minimum version: 1.0.0 +# +# Defines {MALLOC,XMALLOC,XTMALLOC}_ZERO_CFLAGS appropriately if +# malloc(0) returns NULL. Packages should add one of these cflags to +# their AM_CFLAGS (or other appropriate *_CFLAGS) to use them. +AC_DEFUN([NX_CHECK_MALLOC_ZERO],[ +AC_ARG_ENABLE(malloc0returnsnull, + AS_HELP_STRING([--enable-malloc0returnsnull], + [malloc(0) returns NULL (default: auto)]), + [MALLOC_ZERO_RETURNS_NULL=$enableval], + [MALLOC_ZERO_RETURNS_NULL=auto]) + +AC_MSG_CHECKING([whether malloc(0) returns NULL]) +if test "x$MALLOC_ZERO_RETURNS_NULL" = xauto; then + AC_RUN_IFELSE([AC_LANG_PROGRAM([ +#include <stdlib.h> +],[ + char *m0, *r0, *c0, *p; + m0 = malloc(0); + p = malloc(10); + r0 = realloc(p,0); + c0 = calloc(0,10); + exit((m0 == 0 || r0 == 0 || c0 == 0) ? 0 : 1); +])], + [MALLOC_ZERO_RETURNS_NULL=yes], + [MALLOC_ZERO_RETURNS_NULL=no], + [MALLOC_ZERO_RETURNS_NULL=yes]) +fi +AC_MSG_RESULT([$MALLOC_ZERO_RETURNS_NULL]) + +if test "x$MALLOC_ZERO_RETURNS_NULL" = xyes; then + MALLOC_ZERO_CFLAGS="-DMALLOC_0_RETURNS_NULL" + XMALLOC_ZERO_CFLAGS=$MALLOC_ZERO_CFLAGS + XTMALLOC_ZERO_CFLAGS="$MALLOC_ZERO_CFLAGS -DXTMALLOC_BC" +else + MALLOC_ZERO_CFLAGS="" + XMALLOC_ZERO_CFLAGS="" + XTMALLOC_ZERO_CFLAGS="" +fi + +AC_SUBST([MALLOC_ZERO_CFLAGS]) +AC_SUBST([XMALLOC_ZERO_CFLAGS]) +AC_SUBST([XTMALLOC_ZERO_CFLAGS]) +]) # NX_CHECK_MALLOC_ZERO + dnl Check to see if we're running under Cygwin32. |