tools/perf compile error: ignoring return value of 'read', declared with attribute warn_unused_result

tools/perf compile error: ignoring return value of 'read', declared with attribute warn_unused_result

[Kevin Winchester]

    CC builtin-stat.o
cc1: warnings being treated as errors
builtin-stat.c: In function 'run_perf_stat':
builtin-stat.c:243: error: ignoring return value of 'read', declared with attribute warn_unused_result
builtin-stat.c:256: error: ignoring return value of 'read', declared with attribute warn_unused_result
make: *** [builtin-stat.o] Error 1

Apparently my version of gcc and/or glibc do not agree with -Werror.  Would the fix be as simple as:

    if *read(go_pipe[0], &buf, 1) < 0) {
            perror("Failed to read go_pipe.");
            exit(1);
    }

?

-- 
Kevin Winchester

Re: tools/perf compile error: ignoring return value of 'read', declared with attribute warn_unused_result

[Ingo Molnar]

* Kevin Winchester <kjwinchester@gmail.com> wrote:

>     CC builtin-stat.o
> cc1: warnings being treated as errors
> builtin-stat.c: In function 'run_perf_stat':
> builtin-stat.c:243: error: ignoring return value of 'read', declared with attribute warn_unused_result
> builtin-stat.c:256: error: ignoring return value of 'read', declared with attribute warn_unused_result
> make: *** [builtin-stat.o] Error 1
> 
> Apparently my version of gcc and/or glibc do not agree with -Werror.  Would the fix be as simple as:
> 
>     if *read(go_pipe[0], &buf, 1) < 0) {
>             perror("Failed to read go_pipe.");
>             exit(1);
>     }
> 
> ?

Yeah, that's Ubuntu doing some must-check-warnings via headers, 
right?

Frederic fixed a bug there yesterday - mind checking the latest 
perfcounters code at:

  http://people.redhat.com/mingo/tip.git/README

?

Thanks,

	Ingo

Re: tools/perf compile error: ignoring return value of 'read', declared with attribute warn_unused_result

[Kevin Winchester]

Ingo Molnar wrote:
> * Kevin Winchester <kjwinchester@gmail.com> wrote:
> 
>>     CC builtin-stat.o
>> cc1: warnings being treated as errors
>> builtin-stat.c: In function 'run_perf_stat':
>> builtin-stat.c:243: error: ignoring return value of 'read', declared with attribute warn_unused_result
>> builtin-stat.c:256: error: ignoring return value of 'read', declared with attribute warn_unused_result
>> make: *** [builtin-stat.o] Error 1
>>
>> Apparently my version of gcc and/or glibc do not agree with -Werror.  Would the fix be as simple as:
>>
>>     if *read(go_pipe[0], &buf, 1) < 0) {
>>             perror("Failed to read go_pipe.");
>>             exit(1);
>>     }
>>
>> ?
> 
> Yeah, that's Ubuntu doing some must-check-warnings via headers, 
> right?
> 
> Frederic fixed a bug there yesterday - mind checking the latest 
> perfcounters code at:
> 
>   http://people.redhat.com/mingo/tip.git/README
> 
> ?
> 

It's Gentoo, actually, but likely the same issue.  I checked tip/master and it does not show the problem.

Thanks for taking the time to look into it,

-- 
Kevin Winchester