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Re: Why "'X' used but never defined" is a warning and not error in gcc?
- From: Oleg Endo <oleg dot endo at t-online dot de>
- To: Ilya Basin <basinilya at gmail dot com>
- Cc: gcc-help at gcc dot gnu dot org
- Date: Mon, 08 Oct 2012 12:27:08 +0200
- Subject: Re: Why "'X' used but never defined" is a warning and not error in gcc?
- References: <133615603.20121008141915@gmail.com>
On Mon, 2012-10-08 at 14:19 +0400, Ilya Basin wrote:
> test.c:
> static void foo();
>
> void bar() {
> foo();
> }
>
> $ gcc -c test.c
> test.c:1: warning: 'foo' used but never defined
>
> Why warning and not error? Another *.o can refer this static function?
>
No, another .o can't refer to this static function. Static functions
are visible only in the translation unit where they are defined.
The code above will generate a symbol reference to 'foo', i.e. a
function call to a non-static function. If it is defined in some
other .o and linked together, the 'foo' from the other .o will be used.
Cheers,
Oleg