dont attempt to create a std::string from NULL in as_string()

diff --git a/janssonxx.h b/janssonxx.h
index 6703f95..b546f7e 100644 (file)
--- a/janssonxx.h
+++ b/janssonxx.h
@@ -155,7 +155,10 @@ public:
 
        // get value cast to specified type
        const char* as_cstring() const { return json_string_value(_value); }
-       std::string as_string() const { return as_cstring(); }
+       std::string as_string() const {
+               const char* tmp = as_cstring();
+               return tmp == 0 ? "" : tmp;
+       }
        int as_integer() const { return json_integer_value(_value); }
        double as_real() const { return json_real_value(_value); }
        double as_number() const { return json_number_value(_value); }