Re: select() stress

[DervishD]

    Hi all :)

 Richard B. Johnson dixit:
> >       /*  ****************************** */
> >       if (select(getdtablesize(), &socklist, NULL, NULL, NULL) < 0)
> >       {
> >         if (errno != EINTR) perror("WeapTerrain");
> > 	continue;
> >       }
> select() takes a file-descriptor as its first argument, not the
> return-value of some function that returns the number of file-
> descriptors. You cannot assume that this number is the same
> as the currently open socket. Just use the socket-value. That's
> the file-descriptor.

    Not at all. 'select()' takes a *number of file descriptors* as
its first argument, meaning the maximum number of file descriptors to
check (it checks only the first N file descriptors, being 'N' the
first argument). Usually that first argument is FD_SETSIZE, but the
result of any function returning a number is right if you know that
the return value is what you want.

    If, for example, FD_SETSIZE is set to UINT_MAX but
getdtablesize() returns 100 ('ulimit' came to mind), it's a good idea
to use the return value of that function. Anyway, IMHO is better to
use FD_SETSIZE.

    See the glibc info for more references.

    Bye and happy coding :)
    Raúl Núñez de Arenas Coronado

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