Mailing-List: contact cygwin-help@sourceware.cygnus.com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@sourceware.cygnus.com Delivered-To: mailing list cygwin@sourceware.cygnus.com From: Chris Faylor Date: Mon, 6 Dec 1999 18:07:43 -0500 To: Ross Smith Cc: cygwin@sourceware.cygnus.com Subject: Re: More than 64 sockets ? Message-ID: <19991206180743.A10476@cygnus.com> Reply-To: cygwin@sourceware.cygnus.com Mail-Followup-To: Ross Smith , cygwin@sourceware.cygnus.com References: <199912061554.JAA15146@hp2.xraylith.wisc.edu> <19991206161728.C2223@cygnus.com> <19991206164843.B9747@cygnus.com> <384C3898.43BD108@ihug.co.nz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <384C3898.43BD108@ihug.co.nz>; from ross.s@ihug.co.nz on Tue, Dec 07, 1999 at 11:28:40AM +1300 On Tue, Dec 07, 1999 at 11:28:40AM +1300, Ross Smith wrote: >Chris Faylor wrote: >> >> On Mon, Dec 06, 1999 at 04:17:28PM -0500, Chris Faylor wrote: >> >On Mon, Dec 06, 1999 at 09:54:39AM -0600, Mumit Khan wrote: >> >>stefan writes: >> >>> Hello, >> >>> >> >>> we were porting a server software to Win9x/NT and had to notice that you >> >>> cannot accept() more than 64 sockets. Why is this ? Can anyone help us ? >> >> >> >>The underlying OS API, WaitForMultipleObjects, has a limit of 64 handles >> >>it can wait on, and that's probably the reason. There are tricks to get >> >>around it, but it requires creating multiple threads. Not pretty. >> > >> >This isn't a problem with cygwin. Cygwin uses the Winsock select() for >> >sockets. There probably is a limit there but it's not 64. >> >> Just to clarify: The "This" above refers to the WaitForMultipleObjects >> limit of 64 handles. This particular hard limit probably does not affect >> cygwin. >> >> There is a hard-coded limit in winsock.h which is probably what is coming >> to play here. > >This section from the Winsock Programming FAQ may be relevant: This may be marginally relevant, but we're talking about Cygwin here. Until a month or so ago, setting FD_SETSIZE to something else would have been guaranteed to fail. In recent snapshots it should work. cgf >> 3.17 - Can I change FD_SETSIZE to make select() wait on more than 64 >> sockets? >> >> You can, but in practice it may not work. Several common Winsock >> stacks and Layered Service Providers limit themselves internally to >> the default value of FD_SETSIZE, 64. However, you can write a test >> program to try this on the systems you plan on supporting, to see if >> they are not limited. Also, you can always send each group of 64 >> sockets to a different thread, so that several calls to select() can >> occur simultaneously. > >(http://www.cyberport.com/~tangent/programming/winsock/) -- Want to unsubscribe from this list? Send a message to cygwin-unsubscribe@sourceware.cygnus.com