1 files changed, 73 insertions, 0 deletions
diff --git a/m4/ac_func_snprintf.m4 b/m4/ac_func_snprintf.m4
new file mode 100644
index 0000000..3b1d43a
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+++ b/m4/ac_func_snprintf.m4
@@ -0,0 +1,73 @@
+dnl From http://autoconf-archive.cryp.to/
+
+dnl @synopsis AC_FUNC_SNPRINTF
+dnl
+dnl Checks for a fully C99 compliant snprintf, in particular checks
+dnl whether it does bounds checking and returns the correct string
+dnl length; does the same check for vsnprintf. If no working snprintf
+dnl or vsnprintf is found, request a replacement and warn the user
+dnl about it. Note: the mentioned replacement is freely available and
+dnl may be used in any project regardless of it's licence (just like
+dnl the autoconf special exemption).
+dnl
+dnl @category C
+dnl @author Rüdiger Kuhlmann <info@ruediger-kuhlmann.de>
+dnl @version 2002-09-26
+dnl @license AllPermissive
+
+AC_DEFUN([AC_FUNC_SNPRINTF],
+[AC_CHECK_FUNCS(snprintf vsnprintf)
+AC_MSG_CHECKING(for working snprintf)
+AC_CACHE_VAL(ac_cv_have_working_snprintf,
+[AC_TRY_RUN(
+[#include <stdio.h>
+
+int main(void)
+{
+    char bufs[5] = { 'x', 'x', 'x', '\0', '\0' };
+    char bufd[5] = { 'x', 'x', 'x', '\0', '\0' };
+    int i;
+    i = snprintf (bufs, 2, "%s", "111");
+    if (strcmp (bufs, "1")) exit (1);
+    if (i != 3) exit (1);
+    i = snprintf (bufd, 2, "%d", 111);
+    if (strcmp (bufd, "1")) exit (1);
+    if (i != 3) exit (1);
+    exit(0);
+}], ac_cv_have_working_snprintf=yes, ac_cv_have_working_snprintf=no, ac_cv_have_working_snprintf=cross)])
+AC_MSG_RESULT([$ac_cv_have_working_snprintf])
+AC_MSG_CHECKING(for working vsnprintf)
+AC_CACHE_VAL(ac_cv_have_working_vsnprintf,
+[AC_TRY_RUN(
+[#include <stdio.h>
+#include <stdarg.h>
+
+int my_vsnprintf (char *buf, const char *tmpl, ...)
+{
+    int i;
+    va_list args;
+    va_start (args, tmpl);
+    i = vsnprintf (buf, 2, tmpl, args);
+    va_end (args);
+    return i;
+}
+
+int main(void)
+{
+    char bufs[5] = { 'x', 'x', 'x', '\0', '\0' };
+    char bufd[5] = { 'x', 'x', 'x', '\0', '\0' };
+    int i;
+    i = my_vsnprintf (bufs, "%s", "111");
+    if (strcmp (bufs, "1")) exit (1);
+    if (i != 3) exit (1);
+    i = my_vsnprintf (bufd, "%d", 111);
+    if (strcmp (bufd, "1")) exit (1);
+    if (i != 3) exit (1);
+    exit(0);
+}], ac_cv_have_working_vsnprintf=yes, ac_cv_have_working_vsnprintf=no, ac_cv_have_working_vsnprintf=cross)])
+AC_MSG_RESULT([$ac_cv_have_working_vsnprintf])
+if test x$ac_cv_have_working_snprintf$ac_cv_have_working_vsnprintf != "xyesyes"; then
+  AC_LIBOBJ(snprintf)
+  AC_MSG_WARN([Will use fallback (v)snprintf() implementation.])
+  AC_DEFINE(PREFER_PORTABLE_SNPRINTF, 1, "enable replacement (v)snprintf if system (v)snprintf is broken")
+fi])