How safe and reliable are C++ String Literals?
- by DoctorT
So, I'm wanting to get a better grasp on how string literals in C++ work. I'm mostly concerned with situations where you're assigning the address of a string literal to a pointer, and passing it around. For example:
char* advice = "Don't stick your hands in the toaster.";
Now lets say I just pass this string around by copying pointers for the duration of the program. Sure, it's probably not a good idea, but I'm curious what would actually be going on behind the scenes.
For another example, let's say we make a function that returns a string literal:
char* foo()
{
// function does does stuff
return "Yikes!"; // somebody's feeble attempt at an error message
}
Now lets say this function is called very often, and the string literal is only used about half the time it's called:
// situation #1: it's just randomly called without heed to the return value
foo();
// situation #2: the returned string is kept and used for who knows how long
char* retVal = foo();
In the first situation, what's actually happening? Is the string just created but not used, and never deallocated?
In the second situation, is the string going to be maintained as long as the user finds need for it? What happens when it isn't needed anymore... will that memory be freed up then (assuming nothing points to that space anymore)?
Don't get me wrong, I'm not planning on using string literals like this. I'm planning on using a container to keep my strings in check (probably std::string). I'm mostly just wanting to know if these situations could cause problems either for memory management or corrupted data.
