Re: [PATCH 3/4] tools/nolibc: move FD_* definitions to sys/select.h

[Willy Tarreau <w@1wt.eu>]

On Mon, Jun 23, 2025 at 04:56:18AM +0200, Willy Tarreau wrote:
> On Sun, Jun 22, 2025 at 09:58:52PM +0200, Thomas Weißschuh wrote:
> > On 2025-06-22 09:19:58+0200, Willy Tarreau wrote:
> > > Hi Thomas,
> > > 
> > > On Sat, Jun 21, 2025 at 10:21:47AM +0200, Thomas Weißschuh wrote:
> > > > On 2025-06-20 12:02:50+0200, Willy Tarreau wrote:
> > > > > Modern programs tend to include sys/select.h to get FD_SET() and
> > > > > FD_CLR() definitions as well as struct fd_set, but in our case it
> > > > > didn't exist. Let's move these definitions from types.h to sys/select.h
> > > > > to help port existing programs.
> > > > > 
> > > > > Signed-off-by: Willy Tarreau <w@1wt.eu>
> > > > 
> > > > <snip>
> > > > 
> > > > > diff --git a/tools/include/nolibc/types.h b/tools/include/nolibc/types.h
> > > > > index 16c6e9ec9451f..0b51ede4e0a9c 100644
> > > > > --- a/tools/include/nolibc/types.h
> > > > > +++ b/tools/include/nolibc/types.h
> > > > > @@ -10,6 +10,7 @@
> > > > >  #ifndef _NOLIBC_TYPES_H
> > > > >  #define _NOLIBC_TYPES_H
> > > > >  
> > > > > +#include "sys/select.h"
> > > > 
> > > > Is this really necessary?
> > > 
> > > Not sure what you mean. Do you mean that you would have preferred it
> > > to be included from nolibc.h instead (which I'm equally fine with) or
> > > that you'd prefer to have an empty sys/select.h ?
> > 
> > The former.
> 
> OK thanks, you're right, that's more consistent with the rest,
> I'll do that and push it.

Trying it has reopened the circular dependencies can of worms :-(
It's the same problem as usual that we've worked around till now
by placing some types in types.h, except that this time fd_set is
defined based on the macros FD_* that I moved to sys/select.h.

I'm giving up on this one for now as I don't want us to revisit
that painful dependencies sequence. In theory it should be as simple
as guarding types and function definitions independently, but in
reality it's never as rocket science as it can also pop up in macros
and rare typedefs.

Instead I'll just provide a stub for sys/select.h just like for
inttypes so that user code compiles without changing existing files.

Willy