bada C++ std::stringstream

Question

bada crashed on stringstream read.

json::Object objDocument = d();
std::stringstream stream;
json::Writer::Write(objDocument, stream);
json::Object objDocument2;
json::Reader::Read(objDocument2, stream); // <=== crash

or like this:

std::string *requestString = new std::string(data);
AppLog(requestString->c_str()); // <=== contains correct data
std::stringstream stream;
stream << *requestString;
const char *ddd = stream.str().c_str();
AppLog(ddd); // <==== contains random data

How can I solve it?
Who had ideas or same experience?

Answer 1

The string stream.str() is a temporary which is destroyed right after you use it to get c_str() after which the pointer is no longer valid.

If you save a reference in a temporary the string will stick around:

std::string ddd_str = stream.str();
const char *ddd = ddd_str.c_str();
// ddd_str is still in scope and so ddd is still valid...

Answer 2

The first problem is probably a seek issue. After the write, the current position in the stringstream is at the end, but you want to read from the start.