Compile warnings

Hi,

Every now and then I see an 'unused result' warning come by during building. What is the general attitude towards these warnings? Remove them (by properly checking)? Or leave them be as a kind of documentation -- we know we're ignoring the info, but it's good to be reminded?

Thanks, Frans

On Mon, Nov 14, 2011 at 15:55, Frans Klaver <fransklaver@gmail.com> wrote:

Under what OS / version and compiler / version and what's the warning? Paste the full warning(s) you get verbatim.

On Mon, 14 Nov 2011 17:58:20 +0100, Ævar Arnfjörð Bjarmason <avarab@gmail.com> wrote:

This question was triggered by

     warning: ignoring return value of ‘fwrite’, declared with attribute  
warn_unused_result

appearing in diff.c, graph.c, grep.c and several others. I'm using gentoo linux, gcc 4.5.3.

So the specific question would be, do these fwrites need to be checked?

"Frans Klaver" <fransklaver@gmail.com> writes:

A callsite of a function whose return value is better checked should be checked (e.g. not checking return from close(2) or write(2) in a non-error codepath), but there is no strong mechanical "General attitude".

Sprinkling (void) that casts the return values all over the place makes our code illegible, and we do not prefer it as a solution. A function that returns a value that is useful for some callers but can be safely ignored by others is sometimes an indication of a poor API, and for our own code, we tend to prefer designing the API to pass optional pointer to return value from callers that do want to use the return value (and others that do not care about the return value pass NULL).