RE: select() - Linux vs. BSD

[David Schwartz]

> I would have said just the opposite.  That if it you have a large
> number of
> handles you're waiting on, and you have to go back through and
> set the bits
> everytime you timeout that you would incur a larger overhead.  From the
> perspective of my application, it would have been more efficient
> to not zero
> them (I was waiting on a number of serial channels, and the
> timeout was used
> to periodically pump more data to the serial channel.  When I
> received data,
> I buffered it, and another thread took care of processing it).

	The usual implementation is you have a 'permanent' fd_set and a 'temporary'
fd_set. Before each call to select, you memcpy the permanent fd_set into the
temporary and pass the temporary to select. If you wish to stop selecting
for read or write on a given socket, you remove it from the appropriate
permanent set. This way you don't have to twiddle too many bits.

	DS