Re: [OT] Interrupting select

["Peter T. Breuer" <ptb@it.uc3m.es>]

"Mark Hahn wrote:"
> >              while (1) {
> >                  int res = select(n,rfds,wfds,efds,&timeout);
> >                  if (res > 0)
> >                     return res;    // data or error is expected
> >                  if (res == 0) {
> >                     return -ETIME; // timeo in select
> >                  }
> >              }
> > 
> > A resounding "no". kill -9 hurts it but it's invulnerable to everything
> > else.
> 
> um, shouldn't you be testing for res==-1, as well?
> specifically that condition and errno==EINTR is how I'd expect
> signals to effect the loop...

Possibly .. if so that's the answer. But the man page doesn't say so:

          tained in the descriptor sets, which may be zero if the
          timeout expires before anything interesting happens.  On
          error, -1 is returned, and errno is set appropriately;

I assumed that "error" is something like trying to  watch for a
negative number or zero descriptors, or having a fd_set that doesn't
contain open fd's. The reason I assumed that is because EINTR is not
listed as a possible:

    
ERRORS
       EBADF   An invalid file descriptor was given in one of the
               sets.
       EINTR   A non blocked signal was caught.
       EINVAL  n is negative.
       ENOMEM  select was unable to allocate memory for  internal
               tables.

But I'm willing to give it a try! Thanks!

Now back to your regularly scheduled programs ...

Peter