On 1 Jun 2001, Andreas Jaeger wrote:
> #include "sys/tas.h"
> +
> +#ifdef __NR__test_and_set
> +# ifdef __ASSUME__TEST_AND_SET
> +# define __have_no__test_and_set 0
>
> Don't add this, compare how we do it in similar cases.
Hmm, I looked at sysdeps/unix/sysv/linux/getcwd.c. It does it in a
similar way. What's wrong with this approach? I'm just asking -- it
looks I do not always guess glibc rules right and not everything is
documented.
Actually I tried to avoid macros if at all possible but gcc refuses to
eliminate code even if that's something like:
static const int var = 1;
<...>
if (var)
<...>
It still generates the code to check the value of var, sigh...
Also I feel a bit uneasy about placing the "#ifdef
__ASSUME__TEST_AND_SET" condition outside -- __NR__test_and_set might be
undefined due to outdated kernel headers even if someone specified the
--enable-kernel option. Is it considered justified within glibc to bail
out at the compilation time in this case?
> extern int _test_and_set (int *p, int v) __THROW;
> +extern int ___test_and_set (int *p, int v) __THROW;
>
> Why do you export this here?
It's a syscall wrapper. We want to export syscall wrappers, don't we?
And if we export a symbol, we should also declare it -- programs declaring
library symbols themselves are broken and doomed to fail sooner or later
-- have you seen what happens on glibc systems to old programs which
declare <string.h> functions due to the lack of appropriate declarations
in system headers at one time?
If we don't want to export the wrapper, then fine -- I'll remove both the
symbol and the declaration.
Maciej
--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +
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