Hi Ron,
On Sat, Nov 29, 2008 at 11:50 PM, Ron Murray <[EMAIL PROTECTED]> wrote:
> Package: manpages-dev
> Version: 3.05-1
> Severity: normal
>
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> The basename (3) man page says that there are two different versions
> of basename(): the POSIX one and the GNU version. This is
> correct. However, it goes on to say that you get the GNU version with
>
> #define _GNU_SOURCE
> #include <string.h>
>
> Confusingly, it also says (a little further down the page):
>
>> With glibc, one gets the POSIX version of basename() when <libgen.h> is
>> included, and the GNU version otherwise.
>
> Both are actually incorrect. If you have a program with
>
>> #include <stdio.h>
>>
>> int main(void)
>> {
>> char *p, *path = "/usr/nowhere/nothing";
>>
>> p = basename(path);
>>
>> return 0;
>> }
>
> and try to compile it, you'll get
>
>> bt.c: In function 'main':
>> bt.c:7: warning: assignment makes pointer from integer without a cast
>
> (since basename hasn't been defined, its return type defaults to
> 'int').
>
> Defining _GNU_SOURCE and including string.h, as the man page suggests,
> makes no difference. In fact, /usr/include/string.h doesn't use
> _GNU_SOURCE at all (though it does mention it in passing).
>
> If you #define __USE_GNU instead, however, then basename() is defined
> as the GNU version, and no compiler warnings result (the basename()
> definition in string.h is contained in a "#ifdef __USE_GNU"
> construct).
Hmmmm....
$ cat f.c
#include <string.h>
#include <stdio.h>
int main(void)
{
char *p, *path = "/usr/nowhere/nothing";
p = basename(path);
return 0;
}
$ cc f.c
f.c: In function âmainâ:
f.c:8: warning: assignment makes pointer from integer without a cast
As you desribed...
But:
$ cc -D_GNU_SOURCE f.c
$
works fine.
> To be honest, I'm not sure whether this is a manpage error or a
> glibc/header file error, but this seemed a good place to start.
I think the bug report is in error. Have a thorough read of
feature_test_macros(7).
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git
man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html
Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html
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