Re: [Libexif-devel] Error handling

[Lutz <lu...@us...>]

On Mon, 2004-05-17 at 22:39, Joerg Hoh wrote:
> Nope. I don't talk about any kind of interaction with the user on
> application side. I talk about how errors in functions can be detected from
> a calling one.

What does the calling function do with the information 'error occurred'?

> Why do I have to return a struct when no error occurred?

I thought about something like that:

int
main (...) {
    int i1, i2;
    ExifError e = {0, ""};

    /* Calling a function without error checking */
    exif_function (i1, i2, NULL);

    /* Calling a function with error checking */
    exif_function (i1, i2, &e);
    if (e.id != 0) 
        printf ("Error %i occurred: %s.\n", e.id, e.msg);
}

> On high-level
> functions (which will be be called from application side) we can think
> about such a solution, but not on low-level.

As long as the low-level part of the library returns enough information
to enable the user (or the one to whom the user complains) to understand
the problem, I agree with you. Note that at the end of the chain of
calling functions, there is always a user.

Lutz