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ccoding-stylegoto

Is GOTO considered harmless when jumping to cleanup at the end of function?

The goto statement has been examined at great length in several SO discussions (see this and that), and I certainly don't want to revive those heated debates.

Instead, I'd like to concentrate on a single use case of gotos and discuss its value and possible alternatives.

Consider the following code snippet, which is common in (at least my own) FSMs:

while (state = next_state()) {
        switch (state) {
                case foo:
                        /* handle foo, and finally: */
                        if (error) goto cleanup;
                        break;
                case bar:
                        /* handle bar, and finally: */
                        if (error) goto cleanup;
                        break;
                /* ...other cases... */
        }
}

return ok;

cleanup:
/* do some cleanup, i.e. free() local heap requests, adjust global state, and then: */
return error;

Swapping out the cleanup stuff in a separate function just in order to save the gotos seems awkward. On the other hand, we've been raised to condemn the use of gotos wherever possible.

My question: is my code example considered good style?
If not, are there feasible alternatives available?

Please adhere to the specific usage of goto described above. I don't want to delve into yet another discussion about the general use of goto.

Solution

  • Your usage of goto is ok. It doesn't break the 2 good ways to use goto.

    1. gotos MUST go down (a few lines) in the source
    2. The innermost block of goto labels MUST contain the goto statements