Cygwin 3.6: clang cannot use /usr/include/unistd.h, issue with |setproctitle_init()| ...

[Corinna Vinschen]

Guys, I already applied a patch.

Thanks,
Corinna

On Mar  5 15:51, Glenn Strauss via Cygwin wrote:
> On Wed, Mar 05, 2025 at 08:27:53PM +0000, Lavrentiev, Anton (NIH/NLM/NCBI) [C] via Cygwin wrote:
> > >  We could change this to a macro instead:
> > >
> > > -static inline void setproctitle_init (int, char *[], char *[]) {}
> > > +#define setproctitle_init(c, a, e)
> > 
> > Changing to the empty marco removes the side effects in the arguments (such as len++, for example),
> > which may silently break existing code -- so I think it's not a good idea.  If the idea to use the empty
> > arguments was not to implicitly document them (because the API was slated for removal, IIRC), then
> > naming them just with "arg1", "arg2" (rather than leaving empty altogether) should help better, IMO.
> > 
> > Anton Lavrentiev
> > Contractor NIH/NLM/NCBI
> 
> If you want the side effects of the arguments and still want a macro:
> 
>   #define setproctitle_init(c, a, e) \
>     do { (void)(c); (void)(a); (void)(e); } while (0)
> 
> or, since it is unlikely (though possible) that someone has defined a
> single-letter macro for 'c', 'a', or 'b':
> 
> static inline void setproctitle_init (int c, char *a[], char *b[])
> {
>     (void)(c);
>     (void)(a);
>     (void)(e);
> }
> 
> or use the intended, more descriptive names in the prototype
> 
> static inline void setproctitle_init (int argc, char *argv[], char *envp[])
> {
>     (void)(argc);
>     (void)(argv);
>     (void)(envp);
> }
> 
> If gcc or clang, you could also add __attribute__((__unused__)),
> though it should probaby be its own macro so that it could be no-op for
> certain compilers:
> 
> There is also [[maybe_unused]]
> https://clang.llvm.org/docs/AttributeReference.html#maybe-unused-unused
> https://learn.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-4-c4189?view=msvc-170
> 
> #ifndef __attribute_unused__
> #ifdef _MSC_VER
> #define __attribute_unused__ [[maybe_unused]]
> #else
> #define __attribute_unused__ __attribute__((__unused__)),
> #endif
> #endif
> 
> static inline void setproctitle_init (int argc     __attribute_unused__,
>                                       char *argv[] __attribute_unused__,
>                                       char *envp[] __attribute_unused__)
> {
>     (void)(argc);
>     (void)(argv);
>     (void)(envp);
> }
> 
> Cheers, Glenn
> 
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