c-str

This is from a small library that I found online: const char* GetHandStateBrief(const PostFlopState* state) { static std::ostringstream out; // ... rest of the function ... return out.str().c_str() } In my code I am doing this: const char *d = GetHandStateBrief(&post); std::cout<< d << std::endl; Now, at first d contained garbage. I then realized that the C string I am getting from the function is destroyed when the function returns because std::ostringstream is allocated on the stack. So I added: return strdup( out.str().c_str()); And now I can get the text I need from the function. I have

I have read several places that the difference between c_str() and data() (in STL and other implementations) is that c_str() is always null terminated while data() is not. As far as I have seen in actual implementations, they either do the same or data() calls c_str() . What am I missing here? Which one is more correct to use in which scenarios? Scott Langham The documentation is correct. Use c_str() if you want a null terminated string. If the implementers happend to implement data() in terms of c_str() you don't have to worry, still use data() if you don't need the string to be null