misc/sys/select.h

   1 /* `fd_set' type and related macros, and `select'/`pselect' declarations.
   2    Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 /*      POSIX 1003.1g: 6.2 Select from File Descriptor Sets <sys/select.h>  */
  21
  22 #ifndef _SYS_SELECT_H
  23 #define _SYS_SELECT_H   1
  24
  25 #include <features.h>
  26
  27 /* Get definition of needed basic types.  */
  28 #include <bits/types.h>
  29
  30 /* Get __FD_* definitions.  */
  31 #include <bits/select.h>
  32
  33 /* Get __sigset_t.  */
  34 #include <bits/sigset.h>
  35
  36 /* Get definition of timer specification structures.  */
  37 #define __need_timespec
  38 #include <time.h>
  39
  40 __BEGIN_DECLS
  41
  42 /* This declaration puts `struct timeval' in global scope even if
  43    <sys/time.h> has not been included to define it.  That way the
  44    `select' prototype below will not conflict with a later definition
  45    of `struct timeval'.  */
  46 struct timeval;
  47
  48 typedef __fd_mask fd_mask;
  49
  50 /* Representation of a set of file descriptors.  */
  51 typedef __fd_set fd_set;
  52
  53 /* Maximum number of file descriptors in `fd_set'.  */
  54 #define FD_SETSIZE              __FD_SETSIZE
  55
  56 #ifdef __USE_MISC
  57 /* Number of bits per word of `fd_set' (some code assumes this is 32).  */
  58 # define NFDBITS                __NFDBITS
  59 #endif
  60
  61
  62 /* Access macros for `fd_set'.  */
  63 #define FD_SET(fd, fdsetp)      __FD_SET ((fd), (fdsetp))
  64 #define FD_CLR(fd, fdsetp)      __FD_CLR ((fd), (fdsetp))
  65 #define FD_ISSET(fd, fdsetp)    __FD_ISSET ((fd), (fdsetp))
  66 #define FD_ZERO(fdsetp)         __FD_ZERO (fdsetp)
  67
  68
  69 /* Check the first NFDS descriptors each in READFDS (if not NULL) for read
  70    readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
  71    (if not NULL) for exceptional conditions.  If TIMEOUT is not NULL, time out
  72    after waiting the interval specified therein.  Returns the number of ready
  73    descriptors, or -1 for errors.  */
  74 extern int __select __P ((int __nfds, __fd_set *__readfds,
  75                           __fd_set *__writefds, __fd_set *__exceptfds,
  76                           struct timeval *__timeout));
  77 extern int select __P ((int __nfds, __fd_set *__readfds,
  78                         __fd_set *__writefds, __fd_set *__exceptfds,
  79                         struct timeval *__timeout));
  80
  81 #ifdef __USE_GNU
  82 /* XXX Once/if POSIX.1g gets official this prototype will be available
  83    when defining __USE_POSIX.  */
  84 /* Same as above only that the TIMEOUT value is given with higher
  85    resolution and a sigmask which is been set temporarily.  This version
  86    should be used.  */
  87 extern int pselect __P ((int __nfds, __fd_set *__readfds,
  88                          __fd_set *__writefds, __fd_set *__exceptfds,
  89                          const struct timespec *__timeout,
  90                          const __sigset_t *__sigmask));
  91 #endif
  92
  93 __END_DECLS
  94
  95 #endif /* sys/select.h */