1 | /* `fd_set' type and related macros, and `select'/`pselect' declarations. |
2 | Copyright (C) 1996-2019 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/types/sigset_t.h> |
34 | |
35 | /* Get definition of timer specification structures. */ |
36 | #include <bits/types/time_t.h> |
37 | #include <bits/types/struct_timeval.h> |
38 | #ifdef __USE_XOPEN2K |
39 | # include <bits/types/struct_timespec.h> |
40 | #endif |
41 | |
42 | #ifndef __suseconds_t_defined |
43 | typedef __suseconds_t suseconds_t; |
44 | # define __suseconds_t_defined |
45 | #endif |
46 | |
47 | |
48 | /* The fd_set member is required to be an array of longs. */ |
49 | typedef long int __fd_mask; |
50 | |
51 | /* Some versions of <linux/posix_types.h> define this macros. */ |
52 | #undef __NFDBITS |
53 | /* It's easier to assume 8-bit bytes than to get CHAR_BIT. */ |
54 | #define __NFDBITS (8 * (int) sizeof (__fd_mask)) |
55 | #define __FD_ELT(d) ((d) / __NFDBITS) |
56 | #define __FD_MASK(d) ((__fd_mask) (1UL << ((d) % __NFDBITS))) |
57 | |
58 | /* fd_set for select and pselect. */ |
59 | typedef struct |
60 | { |
61 | /* XPG4.2 requires this member name. Otherwise avoid the name |
62 | from the global namespace. */ |
63 | #ifdef __USE_XOPEN |
64 | __fd_mask fds_bits[__FD_SETSIZE / __NFDBITS]; |
65 | # define __FDS_BITS(set) ((set)->fds_bits) |
66 | #else |
67 | __fd_mask __fds_bits[__FD_SETSIZE / __NFDBITS]; |
68 | # define __FDS_BITS(set) ((set)->__fds_bits) |
69 | #endif |
70 | } fd_set; |
71 | |
72 | /* Maximum number of file descriptors in `fd_set'. */ |
73 | #define FD_SETSIZE __FD_SETSIZE |
74 | |
75 | #ifdef __USE_MISC |
76 | /* Sometimes the fd_set member is assumed to have this type. */ |
77 | typedef __fd_mask fd_mask; |
78 | |
79 | /* Number of bits per word of `fd_set' (some code assumes this is 32). */ |
80 | # define NFDBITS __NFDBITS |
81 | #endif |
82 | |
83 | |
84 | /* Access macros for `fd_set'. */ |
85 | #define FD_SET(fd, fdsetp) __FD_SET (fd, fdsetp) |
86 | #define FD_CLR(fd, fdsetp) __FD_CLR (fd, fdsetp) |
87 | #define FD_ISSET(fd, fdsetp) __FD_ISSET (fd, fdsetp) |
88 | #define FD_ZERO(fdsetp) __FD_ZERO (fdsetp) |
89 | |
90 | |
91 | __BEGIN_DECLS |
92 | |
93 | /* Check the first NFDS descriptors each in READFDS (if not NULL) for read |
94 | readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS |
95 | (if not NULL) for exceptional conditions. If TIMEOUT is not NULL, time out |
96 | after waiting the interval specified therein. Returns the number of ready |
97 | descriptors, or -1 for errors. |
98 | |
99 | This function is a cancellation point and therefore not marked with |
100 | __THROW. */ |
101 | extern int select (int __nfds, fd_set *__restrict __readfds, |
102 | fd_set *__restrict __writefds, |
103 | fd_set *__restrict __exceptfds, |
104 | struct timeval *__restrict __timeout); |
105 | |
106 | #ifdef __USE_XOPEN2K |
107 | /* Same as above only that the TIMEOUT value is given with higher |
108 | resolution and a sigmask which is been set temporarily. This version |
109 | should be used. |
110 | |
111 | This function is a cancellation point and therefore not marked with |
112 | __THROW. */ |
113 | extern int pselect (int __nfds, fd_set *__restrict __readfds, |
114 | fd_set *__restrict __writefds, |
115 | fd_set *__restrict __exceptfds, |
116 | const struct timespec *__restrict __timeout, |
117 | const __sigset_t *__restrict __sigmask); |
118 | #endif |
119 | |
120 | |
121 | /* Define some inlines helping to catch common problems. */ |
122 | #if __USE_FORTIFY_LEVEL > 0 && defined __GNUC__ |
123 | # include <bits/select2.h> |
124 | #endif |
125 | |
126 | __END_DECLS |
127 | |
128 | #endif /* sys/select.h */ |
129 | |