1 /* `fd_set' type and related macros, and `select'/`pselect' declarations.
2 Copyright (C) 1996-2003, 2009 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 * (int) 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 */
131