copy from intranet.

libopts/compat/snprintf.c

@@ -0,0 +1,60 @@
+
+#ifndef HAVE_VPRINTF
+#include "choke-me: no vprintf and no snprintf"
+#endif
+
+#if defined(HAVE_STDARG_H)
+#  include <stdarg.h>
+#  ifndef   VA_START
+#    define VA_START(a, f)  va_start(a, f)
+#    define VA_END(a)       va_end(a)
+#  endif /* VA_START */
+#  define SNV_USING_STDARG_H
+
+#elif defined(HAVE_VARARGS_H)
+#  include <varargs.h>
+#  ifndef   VA_START
+#    define VA_START(a, f) va_start(a)
+#    define VA_END(a)    va_end(a)
+#  endif /* VA_START */
+#  undef  SNV_USING_STDARG_H
+
+#else
+#  include "must-have-stdarg-or-varargs"
+#endif
+
+static int
+snprintf(char *str, size_t n, char const *fmt, ...)
+{
+    va_list ap;
+    int rval;
+
+#ifdef VSPRINTF_CHARSTAR
+    char *rp;
+    VA_START(ap, fmt);
+    rp = vsprintf(str, fmt, ap);
+    VA_END(ap);
+    rval = strlen(rp);
+
+#else
+    VA_START(ap, fmt);
+    rval = vsprintf(str, fmt, ap);
+    VA_END(ap);
+#endif
+
+    if (rval > n) {
+        fprintf(stderr, "snprintf buffer overrun %d > %d\n", rval, (int)n);
+        abort();
+    }
+    return rval;
+}
+
+static int
+vsnprintf( char *str, size_t n, char const *fmt, va_list ap )
+{
+#ifdef VSPRINTF_CHARSTAR
+    return (strlen(vsprintf(str, fmt, ap)));
+#else
+    return (vsprintf(str, fmt, ap));
+#endif
+}