From b3bd918f29485681ece900e3f38b90f1ac9b1313 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Can=20Geli=C5=9F?= <geliscan@gmail.com>
Date: Sat, 21 Oct 2017 22:58:24 +0300
Subject: [PATCH] Fix comparison bw integer and pointer (#4155)

* Fix comparison bw integer and pointer

Error: ISO C++ forbids comparison between pointer and integer [-fpermissive]

* Check for nullptr input string.
---
 xs/src/boost/nowide/cenv.hpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/xs/src/boost/nowide/cenv.hpp b/xs/src/boost/nowide/cenv.hpp
index 5f6d084af..5b41b8e8d 100755
--- a/xs/src/boost/nowide/cenv.hpp
+++ b/xs/src/boost/nowide/cenv.hpp
@@ -99,9 +99,11 @@ namespace nowide {
     ///
     inline int putenv(char *string)
     {
+        if (string == nullptr) return -1;
         char const *key = string;
         char const *key_end = string;
-        while(*key_end!='=' && key_end!='\0')
+        
+        while(*key_end!='=' && *key_end!='\0')
             key_end++;
         if(*key_end == '\0')
             return -1;