In C++11, can the characters in the array pointed to by string::c_str() be altered?

`std::string::c_str()` returns a pointer to an array that contains a null-terminated sequence of characters (i.e., a C-string) representing the current value of the string object. In C++98 it was required that "a program shall not alter any of the characters in this sequence". This was encouraged by returning a const char* . IN C++11, the "pointer returned points to the internal array currently used by the string object to store the characters that conform its value", and I believe the requirement not to modify its contents has been dropped. Is this true? Is this code OK in C++11? ``` #include<iostream> #include<string> #include<vector> using namespace std; std::vector<char> buf; void some_func(char* s) { s[0] = 'X'; //function modifies s[0] cout<<s<<endl; } int main() { string myStr = "hello"; buf.assign(myStr.begin(),myStr.end()); buf.push_back('\0'); char* d = buf.data(); //C++11 //char* d = (&buf[0]); //Above line for C++98 some_func(d); //OK in C++98 some_func(const_cast<char*>(myStr.c_str())); //OK in C++11 ? //some_func(myStr.c_str()); //Does not compile in C++98 or C++11 cout << myStr << endl; //myStr has been modified return 0; } ```