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Re: "unused parameter" warnings
From: |
Jim Meyering |
Subject: |
Re: "unused parameter" warnings |
Date: |
Sat, 18 Oct 2008 17:30:05 +0200 |
Bruno Haible <address@hidden> wrote:
> Reuben Thomas wrote:
>> gl_anylinked_list2.h: In function ‘gl_linked_node_value’:
>> gl_anylinked_list2.h:124: warning: unused parameter ‘list’
>> gl_anylinked_list2.h: In function ‘gl_linked_node_set_value’:
>> gl_anylinked_list2.h:130: warning: unused parameter ‘list’
>> gl_anylinked_list2.h: In function ‘gl_linked_iterator_free’:
>> gl_anylinked_list2.h:910: warning: unused parameter ‘iterator’
>
> This is only a small part of the effects of '-Wunused-parameter'. Over
> all gnulib, it yields warnings in 289 places, when compiling on Linux.
> See attached log.
>
> You can see that
> - 10 of these warnings alone are from the regex module, which we borrow
> from glibc, and for which we try to minimize the differences to glibc.
> - Many unit tests have a 'main' function which ignores argc and argv;
> there is nothing to warn about.
> - Some of the functions are defined as callbacks, so it is normal that
> the body does not use all parameters.
> - None of the warnings points to a real problem.
>
> Therefore I find it best to ignore this warning.
I understand the sentiment, and it is fine in relatively stable
and carefully-reviewed code.
However, it would be good to accept patches (at least for gnulib's .h
files) that mark each unused parameter with __attribute__ ((__unused__)).
Then, a project that requires use of -Wunused-parameter can use gnulib's
headers without having to relax their standards.
I will accept such patches for the parts I own (both .c and .h files),
although I admit to disliking the seemingly necessary duplication of
the snippet to define __attribute__.