Re: gl_list API

[Ben Pfaff]

On Tue, Apr 6, 2021 at 1:30 PM Bruno Haible <bruno@clisp.org> wrote:
> Paul Eggert wrote:
> > Yes, that would be portable. But that cast indicates another problem
> > with the API. It should return void *, not void const * (think of strchr
> > as the model here).
>
> strchr is a bad model here: You pass it a pointer to a read-only storage
> (such as a literal string) and receive a pointer that you "can" write
> to: The compiler cannot warn about
>    strchr ("literal", 'e') [2] = 'x';

I've gotten in the habit of having two functions in cases like this. If
strchr were designed according to the principles that I try to apply,
we'd have functions like this:

const char *strchr (const char *, int);
char *strchr_rw (char *, int);

The implementation of strchr is then just a wrapper around the
strchr_rw():

const char *
strchr (const char *s, int c)
{
    return strchr_rw ((char *) s, c);
}

although if I'm doing this in PSPP I would probably use CONST_CAST:
    return strchr_rw (CONST_CAST (char *, s), c);