CODEWITHSUNDEEP
c++string
sharptooth
sharptooth

Reputation: 170509

Is returning a string literal address from a function safe and portable?

I need a function to return a string that will only be accessed read-only. The string contents is known at compile time so that I will use a string literal anyway.

I can return something like std::string:

std::string myFunction()
{
   return "string";
}

or return const char*:

const char* myFunction()
{
   return "string";
}

Is the second alternative safe and portable in this scenario?

Upvotes: 15

Views: 2324

Answers (3)

Prasoon Saurav
Prasoon Saurav

Reputation: 92874

Is the second alternative safe and portable in this scenario?

Yes! The storage allocation of string literals is static and they persist for the lifetime of the application.

Upvotes: 14

Philip Potter
Philip Potter

Reputation: 9135

Yes! But beware of this potential gotcha:

char * myFunc() {
    return "Constant string?";
}

Yes, you can convert a string literal to a non-const char *! This will enable you to later break the world by trying to modify the contents of that char *. This "feature" exists for legacy reasons -- string literals are older than const, and were originally defined as char * in C.

g++ throws out an obnoxious warning for this, even in the default mode, thankfully. I don't know if VC++ throws out a warning just as eagerly.

Upvotes: 11

AProgrammer
AProgrammer

Reputation: 52314

Yes. (It isn't different of storing such pointer in a global data structure).

Upvotes: 3

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