From e62eafc2806bf44b934a2c6486251ed41649769c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Branimir=20Karad=C5=BEi=C4=87?= <branimirkaradzic@gmail.com>
Date: Thu, 12 Jan 2017 18:53:47 -0800
Subject: [PATCH] Fixed crash with VS runtime.

---
 src/string.cpp | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/string.cpp b/src/string.cpp
index 7d48bce..8a11080 100644
--- a/src/string.cpp
+++ b/src/string.cpp
@@ -308,10 +308,14 @@ namespace bx
 	int32_t vsnprintf(char* _str, size_t _count, const char* _format, va_list _argList)
 	{
 #if BX_COMPILER_MSVC
-		va_list argListCopy;
-		va_copy(argListCopy, _argList);
-		int32_t len = ::vsnprintf_s(_str, _count, size_t(-1), _format, argListCopy);
-		va_end(argListCopy);
+		int32_t len = -1;
+		if (NULL != _str)
+		{
+			va_list argListCopy;
+			va_copy(argListCopy, _argList);
+			len = ::vsnprintf_s(_str, _count, size_t(-1), _format, argListCopy);
+			va_end(argListCopy);
+		}
 		return -1 == len ? ::_vscprintf(_format, _argList) : len;
 #else
 		return ::vsnprintf(_str, _count, _format, _argList);
@@ -321,10 +325,14 @@ namespace bx
 	int32_t vsnwprintf(wchar_t* _str, size_t _count, const wchar_t* _format, va_list _argList)
 	{
 #if BX_COMPILER_MSVC
-		va_list argListCopy;
-		va_copy(argListCopy, _argList);
-		int32_t len = ::_vsnwprintf_s(_str, _count, size_t(-1), _format, argListCopy);
-		va_end(argListCopy);
+		int32_t len = -1;
+		if (NULL != _str)
+		{
+			va_list argListCopy;
+			va_copy(argListCopy, _argList);
+			len = ::_vsnwprintf_s(_str, _count, size_t(-1), _format, argListCopy);
+			va_end(argListCopy);
+		}
 		return -1 == len ? ::_vscwprintf(_format, _argList) : len;
 #elif defined(__MINGW32__)
 		return ::vsnwprintf(_str, _count, _format, _argList);