--- /dev/null
+
+#include "upb/upb.h"
+#include "upb/port_def.inc"
+
+#ifdef UPB_MSVC_VSNPRINTF
+/* Visual C++ earlier than 2015 doesn't have standard C99 snprintf and
+ * vsnprintf. To support them, missing functions are manually implemented
+ * using the existing secure functions. */
+int msvc_vsnprintf(char* s, size_t n, const char* format, va_list arg) {
+ if (!s) {
+ return _vscprintf(format, arg);
+ }
+ int ret = _vsnprintf_s(s, n, _TRUNCATE, format, arg);
+ if (ret < 0) {
+ ret = _vscprintf(format, arg);
+ }
+ return ret;
+}
+
+int msvc_snprintf(char* s, size_t n, const char* format, ...) {
+ va_list arg;
+ va_start(arg, format);
+ int ret = msvc_vsnprintf(s, n, format, arg);
+ va_end(arg);
+ return ret;
+}
+#endif