1 /* `fd_set' type and related macros, and `select'/`pselect' declarations.
2 Copyright (C) 1996-2015 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, see
17 <http://www.gnu.org/licenses/>. */
18
19 /* POSIX 1003.1g: 6.2 Select from File Descriptor Sets <sys/select.h> */
20
21 #ifndef _SYS_SELECT_H
22 #define _SYS_SELECT_H 1
23
24 #include <features.h>
25
26 /* Get definition of needed basic types. */
27 #include <bits/types.h>
28
29 /* Get __FD_* definitions. */
30 #include <bits/select.h>
31
32 /* Get __sigset_t. */
33 #include <bits/sigset.h>
34
35 #ifndef __sigset_t_defined
36 # define __sigset_t_defined
37 typedef __sigset_t sigset_t;
38 #endif
39
40 /* Get definition of timer specification structures. */
41 #define __need_time_t
42 #define __need_timespec
43 #include <time.h>
44 #define __need_timeval
45 #include <bits/time.h>
46
47 #ifndef __suseconds_t_defined
48 typedef __suseconds_t suseconds_t;
49 # define __suseconds_t_defined
50 #endif
51
52
53 /* The fd_set member is required to be an array of longs. */
54 typedef long int __fd_mask;
55
56 /* Some versions of <linux/posix_types.h> define this macros. */
57 #undef __NFDBITS
58 /* It's easier to assume 8-bit bytes than to get CHAR_BIT. */
59 #define __NFDBITS (8 * (int) sizeof (__fd_mask))
60 #define __FD_ELT(d) ((d) / __NFDBITS)
61 #define __FD_MASK(d) ((__fd_mask) (1UL << ((d) % __NFDBITS)))
62
63 /* fd_set for select and pselect. */
64 typedef struct
65 {
66 /* XPG4.2 requires this member name. Otherwise avoid the name
67 from the global namespace. */
68 #ifdef __USE_XOPEN
69 __fd_mask fds_bits[__FD_SETSIZE / __NFDBITS];
70 # define __FDS_BITS(set) ((set)->fds_bits)
71 #else
72 __fd_mask __fds_bits[__FD_SETSIZE / __NFDBITS];
73 # define __FDS_BITS(set) ((set)->__fds_bits)
74 #endif
75 } fd_set;
76
77 /* Maximum number of file descriptors in `fd_set'. */
78 #define FD_SETSIZE __FD_SETSIZE
79
80 #ifdef __USE_MISC
81 /* Sometimes the fd_set member is assumed to have this type. */
82 typedef __fd_mask fd_mask;
83
84 /* Number of bits per word of `fd_set' (some code assumes this is 32). */
85 # define NFDBITS __NFDBITS
86 #endif
87
88
89 /* Access macros for `fd_set'. */
90 #define FD_SET(fd, fdsetp) __FD_SET (fd, fdsetp)
91 #define FD_CLR(fd, fdsetp) __FD_CLR (fd, fdsetp)
92 #define FD_ISSET(fd, fdsetp) __FD_ISSET (fd, fdsetp)
93 #define FD_ZERO(fdsetp) __FD_ZERO (fdsetp)
94
95
96 __BEGIN_DECLS
97
98 /* Check the first NFDS descriptors each in READFDS (if not NULL) for read
99 readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
100 (if not NULL) for exceptional conditions. If TIMEOUT is not NULL, time out
101 after waiting the interval specified therein. Returns the number of ready
102 descriptors, or -1 for errors.
103
104 This function is a cancellation point and therefore not marked with
105 __THROW. */
106 extern int select (int __nfds, fd_set *__restrict __readfds,
107 fd_set *__restrict __writefds,
108 fd_set *__restrict __exceptfds,
109 struct timeval *__restrict __timeout);
110
111 #ifdef __USE_XOPEN2K
112 /* Same as above only that the TIMEOUT value is given with higher
113 resolution and a sigmask which is been set temporarily. This version
114 should be used.
115
116 This function is a cancellation point and therefore not marked with
117 __THROW. */
118 extern int pselect (int __nfds, fd_set *__restrict __readfds,
119 fd_set *__restrict __writefds,
120 fd_set *__restrict __exceptfds,
121 const struct timespec *__restrict __timeout,
122 const __sigset_t *__restrict __sigmask);
123 #endif
124
125
126 /* Define some inlines helping to catch common problems. */
127 #if __USE_FORTIFY_LEVEL > 0 && defined __GNUC__
128 # include <bits/select2.h>
129 #endif
130
131 __END_DECLS
132
133 #endif /* sys/select.h */
134