Is it safe to pass std::string to C style APIs?

Question

It is well defined C++ to pass std::vector to C APIs that expect an output array like so because std::vector is contiguous:

std::vector myArray(a         


        

Answer 1

cStyleAPI(&myArray[0], arraySize);

If your cStyleAPI receives a char* for input, that is what std::string::c_str() is for.

If it receives a pre-allocated char* for output, then no. In that case, you should use a std::vector or std::array.