Since I can't return a local variable, what's the best way to return a string from a C or C++ function?

Question

As a follow-up to this question:

From what I\'ve seen, this should work as expected:

void greet(){
  char c[] = \"Hello\";
  greetWith(c);
  return;
         


        

Answer 1

You can use either of these:

char const* getIt() {
    return "hello";
}

char * getIt() {
    static char thing[] = "hello";
    return thing;
}

char * getIt() {
    char str[] = "hello";
    char * thing = new char[sizeof str];
    std::strcpy(thing, str);
    return thing;
}

shared_array getIt() {
    char str[] = "hello";
    shared_array thing(new char[sizeof str]);
    std::strcpy(thing.get(), str);
    return thing;
}

The first requires you to not write to the returned string, but also is the simplest you can get. The last uses shared_array which automatically can clean up memory if the reference to the memory is lost (the last shared_array to it goes out of scope). The last and second last must be used if you require a new string everytime you call the function.