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about placing the "#ifdef __ASSUME__TEST_AND_SET" condition outside -- __NR__test_and_set might be undefined due to outdated kernel headers even if someone specified the --enable-kernel option.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 +
