The new overload was added by P0272R1 for C++17. Neither the paper itself nor the links therein discuss why only data was given new overloads but c_str was not. We can only speculate at this point (unless people involved in the discussion chime in), but I’d like to offer the following points for consideration: Even … Read more
c_str returns a const char* that points to a null-terminated string (i.e., a C-style string). It is useful when you want to pass the “contents”¹ of an std::string to a function that expects to work with a C-style string. For example, consider this code: std::string string(“Hello, World!”); std::size_t pos1 = string.find_first_of(‘w’); std::size_t pos2 = static_cast<std::size_t>(std::strchr(string.c_str(), … Read more
The c_str() result becomes invalid if the std::string is destroyed or if a non-const member function of the string is called. So, usually you will want to make a copy of it if you need to keep it around. In the case of your example, it appears that the results of c_str() are used safely, … Read more
c_str returns a const char* that points to a null-terminated string (i.e. a C-style string). It is useful when you want to pass the “contents”¹ of an std::string to a function that expects to work with a C-style string. For example, consider this code: std::string string(“Hello world!”); std::size_t pos1 = string.find_first_of(‘w’); std::size_t pos2 = static_cast<std::size_t>(std::strchr(string.c_str(), … Read more
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 terminated, in some implementation it may turn out to perform better than c_str(). strings … Read more