File: /usr/include/sys/select.h
1 /* `fd_set' type and related macros, and `select'/`pselect' declarations.
2 Copyright (C) 1996,1997,1998,1999,2000,2001 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 #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_timespec
43 #include <time.h>
44 #define __need_timeval
45 #include <bits/time.h>
46
47
48 /* The fd_set member is required to be an array of longs. */
49 typedef long int __fd_mask;
50
51 /* It's easier to assume 8-bit bytes than to get CHAR_BIT. */
52 #define __NFDBITS (8 * sizeof (__fd_mask))
53 #define __FDELT(d) ((d) / __NFDBITS)
54 #define __FDMASK(d) ((__fd_mask) 1 << ((d) % __NFDBITS))
55
56 /* fd_set for select and pselect. */
57 typedef struct
58 {
59 /* XPG4.2 requires this member name. Otherwise avoid the name
60 from the global namespace. */
61 #ifdef __USE_XOPEN
62 __fd_mask fds_bits[__FD_SETSIZE / __NFDBITS];
63 # define __FDS_BITS(set) ((set)->fds_bits)
64 #else
65 __fd_mask __fds_bits[__FD_SETSIZE / __NFDBITS];
66 # define __FDS_BITS(set) ((set)->__fds_bits)
67 #endif
68 } fd_set;
69
70 /* Maximum number of file descriptors in `fd_set'. */
71 #define FD_SETSIZE __FD_SETSIZE
72
73 #ifdef __USE_MISC
74 /* Sometimes the fd_set member is assumed to have this type. */
75 typedef __fd_mask fd_mask;
76
77 /* Number of bits per word of `fd_set' (some code assumes this is 32). */
78 # define NFDBITS __NFDBITS
79 #endif
80
81
82 /* Access macros for `fd_set'. */
83 #define FD_SET(fd, fdsetp) __FD_SET (fd, fdsetp)
84 #define FD_CLR(fd, fdsetp) __FD_CLR (fd, fdsetp)
85 #define FD_ISSET(fd, fdsetp) __FD_ISSET (fd, fdsetp)
86 #define FD_ZERO(fdsetp) __FD_ZERO (fdsetp)
87
88
89 __BEGIN_DECLS
90
91 /* Check the first NFDS descriptors each in READFDS (if not NULL) for read
92 readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
93 (if not NULL) for exceptional conditions. If TIMEOUT is not NULL, time out
94 after waiting the interval specified therein. Returns the number of ready
95 descriptors, or -1 for errors. */
96 extern int select (int __nfds, fd_set *__restrict __readfds,
97 fd_set *__restrict __writefds,
98 fd_set *__restrict __exceptfds,
99 struct timeval *__restrict __timeout) __THROW;
100
101 #ifdef __USE_XOPEN2K
102 /* Same as above only that the TIMEOUT value is given with higher
103 resolution and a sigmask which is been set temporarily. This version
104 should be used. */
105 extern int pselect (int __nfds, fd_set *__restrict __readfds,
106 fd_set *__restrict __writefds,
107 fd_set *__restrict __exceptfds,
108 const struct timespec *__restrict __timeout,
109 const __sigset_t *__restrict __sigmask) __THROW;
110 #endif
111
112 __END_DECLS
113
114 #endif /* sys/select.h */
115