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| -rw-r--r-- | m4/calloc.m4 | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/m4/calloc.m4 b/m4/calloc.m4 new file mode 100644 index 000000000..fbeaaccf1 --- /dev/null +++ b/m4/calloc.m4 @@ -0,0 +1,44 @@ +#serial 1 + +# Determine whether calloc (N, S) works when N*S is zero. +# If so, define HAVE_CALLOC. Otherwise, define calloc to rpl_calloc +# and arrange to use a calloc wrapper function that does work in that case. + +# _AC_FUNC_CALLOC_IF(IF-WORKS, IF-NOT) +# ------------------------------------- +# If `calloc (0, 0)' is properly handled, run IF-WORKS, otherwise, IF-NOT. +AC_DEFUN([_AC_FUNC_CALLOC_IF], +[AC_REQUIRE([AC_HEADER_STDC])dnl +AC_CHECK_HEADERS(stdlib.h) +AC_CACHE_CHECK([for GNU libc compatible calloc], ac_cv_func_calloc_0_nonnull, +[AC_RUN_IFELSE( +[AC_LANG_PROGRAM( +[[#if STDC_HEADERS || HAVE_STDLIB_H +# include <stdlib.h> +#else +char *calloc (); +#endif +]], + [exit (calloc (0, 0) ? 0 : 1);])], + [ac_cv_func_calloc_0_nonnull=yes], + [ac_cv_func_calloc_0_nonnull=no], + [ac_cv_func_calloc_0_nonnull=no])]) +AS_IF([test $ac_cv_func_calloc_0_nonnull = yes], [$1], [$2]) +])# AC_FUNC_CALLOC + + +# AC_FUNC_CALLOC +# --------------- +# Report whether `calloc (0, 0)' is properly handled, and replace calloc if +# needed. +AN_FUNCTION([calloc], [AC_FUNC_CALLOC]) +AC_DEFUN([AC_FUNC_CALLOC], +[_AC_FUNC_CALLOC_IF( + [AC_DEFINE([HAVE_CALLOC], 1, + [Define to 1 if your system has a GNU libc compatible `calloc' + function, and to 0 otherwise.])], + [AC_DEFINE([HAVE_CALLOC], 0) + AC_LIBOBJ([calloc]) + AC_DEFINE([calloc], [rpl_calloc], + [Define to rpl_calloc if the replacement function should be used.])]) +])# AC_FUNC_CALLOC |