/*
* The size parameter specifies the available space, i.e. includes
- * the trailing NUL byte; but Windows's vsnprintf expects the
- * number of characters to write without the trailing NUL.
+ * the trailing NUL byte; but Windows's vsnprintf uses the entire
+ * buffer and avoids the trailing NUL, should the buffer be exactly
+ * big enough for the result. Defining SNPRINTF_SIZE_CORR to 1 will
+ * therefore remove 1 byte from the reported buffer size, so we
+ * always have room for a trailing NUL byte.
*/
#ifndef SNPRINTF_SIZE_CORR
-#if defined(__MINGW32__) && defined(__GNUC__) && __GNUC__ < 4
+#if defined(WIN32) && (!defined(__GNUC__) || __GNUC__ < 4) && (!defined(_MSC_VER) || _MSC_VER < 1900)
#define SNPRINTF_SIZE_CORR 1
#else
#define SNPRINTF_SIZE_CORR 0
#undef vsnprintf
int git_vsnprintf(char *str, size_t maxsize, const char *format, va_list ap)
{
+ va_list cp;
char *s;
int ret = -1;
if (maxsize > 0) {
- ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
+ va_copy(cp, ap);
+ ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, cp);
+ va_end(cp);
if (ret == maxsize-1)
ret = -1;
/* Windows does not NUL-terminate if result fills buffer */
if (! str)
break;
s = str;
- ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
+ va_copy(cp, ap);
+ ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, cp);
+ va_end(cp);
if (ret == maxsize-1)
ret = -1;
}