1 /* `fd_set' type and related macros, and `select'/`pselect' declarations. 2 Copyright (C) 1996-2003, 2009, 2011 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) 1 << ((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