Memory Error with std:ostringstream and -std=c++11? [duplicate]

Answer 1

Take a closer look at this line: const char* stmt = qs.str().c_str();

qs.str() provides you a temporary std::string object from which you take a pointer to inner char* array. Once this line completes its execution, your pointer is no longer valid and something else may (and probably is) stored there.

Try doing this instead:

std::string strstmt(qs.str());
const char* stmt = strstmt.c_str();

Answer 2

const char* stmt = qs.str().c_str();

That extracts a temporary string from qs, takes a pointer to its content, then destroys the temporary leaving the pointer dangling. Using the pointer after this will give undefined behaviour.

To fix it, you could either assign the result of str() to a variable, so that it's no longer temporary, or use this expression as the argument to sqlite3_exec, so that the temporary survives until after that function call. (In the second case, you'd have to remove the first assertion; but that assertion is rather pointless anyway).