Not able to parse large json using json cpp library 1.9.5 version

[rvgm]

this is below code snippet we are using to parse json
auto str = reinterpret_cast<const char*="">(data);
Json::CharReaderBuilder builder;
std::unique_ptr<json::charreader> json_reader(builder.newCharReader());
std::string errorMessage;
return json_reader->parse(str, str + length, msg_out, &errorMessage);</json::charreader></const>

Not able to parse large json using json cpp library 1.9.5, for a small json parse function does return true, but for large json its return false.