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 Message-ID: <384C3898.43BD108@ihug.co.nz> Date: Tue, 07 Dec 1999 11:28:40 +1300 From: Ross Smith Organization: The Internet Group X-Mailer: Mozilla 4.7 [en] (WinNT; I) X-Accept-Language: en MIME-Version: 1.0 To: cygwin@sourceware.cygnus.com Subject: Re: More than 64 sockets ? References: <199912061554.JAA15146@hp2.xraylith.wisc.edu> <19991206161728.C2223@cygnus.com> <19991206164843.B9747@cygnus.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit 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: > 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/) -- Ross Smith The Internet Group, Auckland, New Zealand ======================================================================== "Be careful about using the following code -- I've only proven that it works, I haven't tested it." -- Donald Knuth -- Want to unsubscribe from this list? Send a message to cygwin-unsubscribe@sourceware.cygnus.com