std::string(NULL,0) asserts in MSVC Debug

diff --git a/src/string_piece.h b/src/string_piece.h
index 2f881a2..ad1153e 100644 (file)
--- a/src/string_piece.h
+++ b/src/string_piece.h
@@ -43,7 +43,7 @@ struct StringPiece {
   /// Convert the slice into a full-fledged std::string, copying the
   /// data into a new string.
   string AsString() const {
-    return string(str_, len_);
+    return len_ ? string(str_, len_) : string();
   }
 
   const char* str_;