-// ----------------------------------------------------------------------------
-// $Id$
-// ----------------------------------------------------------------------------
-// Public Domain C Library - http://pdclib.sourceforge.net
-// This code is Public Domain. Use, modify, and redistribute at will.
-// ----------------------------------------------------------------------------
-
-int vsnprintf( char * restrict s, size_t n, const char * restrict format, va_list ap ) { /* TODO */ };
+/* vsnprintf( char *, size_t, const char *, va_list ap )
+
+ This file is part of the Public Domain C Library (PDCLib).
+ Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#include <stdio.h>
+#include <stdarg.h>
+
+#ifndef REGTEST
+#include <_PDCLIB_io.h>
+#include <string.h>
+
+struct state {
+ size_t bufrem;
+ char *bufp;
+};
+
+static size_t strout( void *p, const char *buf, size_t sz )
+{
+ struct state *s = p;
+ size_t copy = s->bufrem >= sz ? sz : s->bufrem;
+ memcpy( s->bufp, buf, copy );
+ s->bufrem -= copy;
+ s->bufp += copy;
+ return sz;
+}
+
+int vsnprintf( char * _PDCLIB_restrict s,
+ size_t n,
+ const char * _PDCLIB_restrict format,
+ _PDCLIB_va_list arg )
+{
+ struct state st;
+ st.bufrem = n;
+ st.bufp = s;
+ int r = _vcbprintf( &st, strout, format, arg );
+ if ( st.bufrem )
+ {
+ *st.bufp = 0;
+ }
+
+ return r;
+}
+
+#endif
+
+#ifdef TEST
+#define _PDCLIB_FILEID "stdio/vsnprintf.c"
+#define _PDCLIB_STRINGIO
+#include <stdint.h>
+#include <stddef.h>
+#include <_PDCLIB_test.h>
+
+static int testprintf( char * s, const char * format, ... )
+{
+ int i;
+ va_list arg;
+ va_start( arg, format );
+ i = vsnprintf( s, 100, format, arg );
+ va_end( arg );
+ return i;
+}
+
+int main( void )
+{
+ char target[100];
+#include "printf_testcases.h"
+ return TEST_RESULTS;
+}
+
+#endif
+