strerror_r(ev, tmp, 0) may return tmp

boostorg · Jun 2, 2024 · 38d63aa · 38d63aa
1 parent d1fb755
commit 38d63aa
Showing 1 changed file with 11 additions and 4 deletions.
diff --git a/include/boost/system/detail/generic_category_message.hpp b/include/boost/system/detail/generic_category_message.hpp
@@ -39,12 +39,19 @@ inline char const * strerror_r_helper( int r, char const * buffer ) noexcept
 
 inline char const * generic_error_category_message( int ev, char * buffer, std::size_t len ) noexcept
 {
-    if ( buffer != nullptr )
+    if( buffer != nullptr )
+    {
         return strerror_r_helper( strerror_r( ev, buffer, len ), buffer );
+    }
+    else
+    {
+        // strerror_r requires non-null buffer pointer
 
-    // strerror_r requires non-null buffer pointer
-    char dummy_buffer[ 1 ];
-    return strerror_r_helper( strerror_r( ev, dummy_buffer, 0 ), buffer );
+        char tmp[ 1 ];
+        char const* r = strerror_r_helper( strerror_r( ev, tmp, 0 ), buffer );
+
+        return r == tmp? nullptr: r;
+    }
 }
 
 inline std::string generic_error_category_message( int ev )