From db197f296fa0d8d1f3b21f8cfa644eb3e0c5971b Mon Sep 17 00:00:00 2001 From: akr Date: Tue, 2 Dec 2008 08:52:19 +0000 Subject: add comment for select behavior on file descriptors over FD_SETSIZE. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@20444 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- include/ruby/intern.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'include/ruby/intern.h') diff --git a/include/ruby/intern.h b/include/ruby/intern.h index a2d4fcb91a..c7a4830b06 100644 --- a/include/ruby/intern.h +++ b/include/ruby/intern.h @@ -201,6 +201,32 @@ int rb_sourceline(void); const char *rb_sourcefile(void); #if defined(NFDBITS) && defined(HAVE_RB_FD_INIT) + +/* + * several Unix platform supports file descriptors bigger than FD_SETSIZE + * in select(2) system call. + * + * - Linux 2.2.12 (?) + * - NetBSD 1.2 (src/sys/kern/sys_generic.c:1.25) + * select(2) documents how to allocate fd_set dynamically. + * http://netbsd.gw.com/cgi-bin/man-cgi?select++NetBSD-4.0 + * - FreeBSD 2.2 (src/sys/kern/sys_generic.c:1.19) + * - OpenBSD 2.0 (src/sys/kern/sys_generic.c:1.4) + * select(2) documents how to allocate fd_set dynamically. + * http://www.openbsd.org/cgi-bin/man.cgi?query=select&manpath=OpenBSD+4.4 + * - HP-UX documents how to allocate fd_set dynamically. + * http://docs.hp.com/en/B2355-60105/select.2.html + * - Solaris 8 has select_large_fdset + * + * When fd_set is not big enough to hold big file descriptors, + * it should be allocated dynamically. + * Note that this assumes fd_set is structured as bitmap. + * + * rb_fd_init allocates the memory. + * rb_fd_term free the memory. + * rb_fd_set may re-allocates bitmap. + */ + typedef struct { int maxfd; fd_set *fdset; -- cgit v1.2.3