misc/sys/select.h

   1 /* `fd_set' type and related macros, and `select'/`pselect' declarations.
   2    Copyright (C) 1996,97,98,99,2000,01,02,2003 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    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 #ifndef __sigset_t_defined
  37 # define __sigset_t_defined
  38 typedef __sigset_t sigset_t;
  39 #endif
  40
  41 /* Get definition of timer specification structures.  */
  42 #define __need_time_t
  43 #define __need_timespec
  44 #include <time.h>
  45 #define __need_timeval
  46 #include <bits/time.h>
  47
  48 #ifndef __suseconds_t_defined
  49 typedef __suseconds_t suseconds_t;
  50 # define __suseconds_t_defined
  51 #endif
  52
  53
  54 /* The fd_set member is required to be an array of longs.  */
  55 typedef long int __fd_mask;
  56
  57 /* Some versions of <linux/posix_types.h> define these macros.  */
  58 #undef  __NFDBITS
  59 #undef  __FDELT
  60 #undef  __FDMASK
  61 /* It's easier to assume 8-bit bytes than to get CHAR_BIT.  */
  62 #define __NFDBITS       (8 * sizeof (__fd_mask))
  63 #define __FDELT(d)      ((d) / __NFDBITS)
  64 #define __FDMASK(d)     ((__fd_mask) 1 << ((d) % __NFDBITS))
  65
  66 /* fd_set for select and pselect.  */
  67 typedef struct
  68   {
  69     /* XPG4.2 requires this member name.  Otherwise avoid the name
  70        from the global namespace.  */
  71 #ifdef __USE_XOPEN
  72     __fd_mask fds_bits[__FD_SETSIZE / __NFDBITS];
  73 # define __FDS_BITS(set) ((set)->fds_bits)
  74 #else
  75     __fd_mask __fds_bits[__FD_SETSIZE / __NFDBITS];
  76 # define __FDS_BITS(set) ((set)->__fds_bits)
  77 #endif
  78   } fd_set;
  79
  80 /* Maximum number of file descriptors in `fd_set'.  */
  81 #define FD_SETSIZE              __FD_SETSIZE
  82
  83 #ifdef __USE_MISC
  84 /* Sometimes the fd_set member is assumed to have this type.  */
  85 typedef __fd_mask fd_mask;
  86
  87 /* Number of bits per word of `fd_set' (some code assumes this is 32).  */
  88 # define NFDBITS                __NFDBITS
  89 #endif
  90
  91
  92 /* Access macros for `fd_set'.  */
  93 #define FD_SET(fd, fdsetp)      __FD_SET (fd, fdsetp)
  94 #define FD_CLR(fd, fdsetp)      __FD_CLR (fd, fdsetp)
  95 #define FD_ISSET(fd, fdsetp)    __FD_ISSET (fd, fdsetp)
  96 #define FD_ZERO(fdsetp)         __FD_ZERO (fdsetp)
  97
  98
  99 __BEGIN_DECLS
 100
 101 /* Check the first NFDS descriptors each in READFDS (if not NULL) for read
 102    readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
 103    (if not NULL) for exceptional conditions.  If TIMEOUT is not NULL, time out
 104    after waiting the interval specified therein.  Returns the number of ready
 105    descriptors, or -1 for errors.
 106
 107    This function is a cancellation point and therefore not marked with
 108    __THROW.  */
 109 extern int select (int __nfds, fd_set *__restrict __readfds,
 110                    fd_set *__restrict __writefds,
 111                    fd_set *__restrict __exceptfds,
 112                    struct timeval *__restrict __timeout);
 113
 114 #ifdef __USE_XOPEN2K
 115 /* Same as above only that the TIMEOUT value is given with higher
 116    resolution and a sigmask which is been set temporarily.  This version
 117    should be used.
 118
 119    This function is a cancellation point and therefore not marked with
 120    __THROW.  */
 121 extern int pselect (int __nfds, fd_set *__restrict __readfds,
 122                     fd_set *__restrict __writefds,
 123                     fd_set *__restrict __exceptfds,
 124                     const struct timespec *__restrict __timeout,
 125                     const __sigset_t *__restrict __sigmask);
 126 #endif
 127
 128 __END_DECLS
 129
 130 #endif /* sys/select.h */