Date: Thu, 20 Jun 1996 21:53:50 +0100 From: "Gary Palmer" <gpalmer@freebsd.org> To: James Raynard <fqueries@jraynard.demon.co.uk> Cc: af@biomath.jussieu.fr, freebsd-questions@freebsd.org Subject: Re: Max first parameter of a Select call? Message-ID: <7073.835304030@palmer.demon.co.uk> In-Reply-To: Your message of "Wed, 19 Jun 1996 14:04:20 GMT." <199606191404.OAA20852@jraynard.demon.co.uk>
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James Raynard wrote in message ID <199606191404.OAA20852@jraynard.demon.co.uk>: > However, <sys/types.h> is a copy of the types.h used in compiling the > kernel, which is where the kernel picks up its value of FD_SETSIZE > from. So a user program can never safely use FD_SETSIZE > 256 without > a kernel re-compile first! It can actually, you get get an error back if you try to set the number of FD's you want to scan (the `nfds' parameter) to be greater than the value of FD_SETSIZE when the kernel was compiled (at least, that's how -stable works, and from a quick glance -current seems the same). The real answer is to make it dynamic and dependant on a read-only sysctl variable or something ... I'm not sure if the bitmap's required by the code will be that forgiving tho :-( Gary -- Gary Palmer FreeBSD Core Team Member FreeBSD: Turning PC's into workstations. See http://www.FreeBSD.ORG/ for info
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