1 /* `fd_set' type and related macros, and `select'/`pselect' declarations. 2 Copyright (C) 1996,97,98,99,2000,01,02,2003 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 these macros. */ 57 #undef __NFDBITS 58 #undef __FDELT 59 #undef __FDMASK 60 /* It's easier to assume 8-bit bytes than to get CHAR_BIT. */ 61 #define __NFDBITS (8 * sizeof (__fd_mask)) 62 #define __FDELT(d) ((d) / __NFDBITS) 63 #define __FDMASK(d) ((__fd_mask) 1 << ((d) % __NFDBITS)) 64 65 /* fd_set for select and pselect. */ 66 typedef struct 67 { 68 /* XPG4.2 requires this member name. Otherwise avoid the name 69 from the global namespace. */ 70 #ifdef __USE_XOPEN 71 __fd_mask fds_bits[__FD_SETSIZE / __NFDBITS]; 72 # define __FDS_BITS(set) ((set)->fds_bits) 73 #else 74 __fd_mask __fds_bits[__FD_SETSIZE / __NFDBITS]; 75 # define __FDS_BITS(set) ((set)->__fds_bits) 76 #endif 77 } fd_set; 78 79 /* Maximum number of file descriptors in `fd_set'. */ 80 #define FD_SETSIZE __FD_SETSIZE 81 82 #ifdef __USE_MISC 83 /* Sometimes the fd_set member is assumed to have this type. */ 84 typedef __fd_mask fd_mask; 85 86 /* Number of bits per word of `fd_set' (some code assumes this is 32). */ 87 # define NFDBITS __NFDBITS 88 #endif 89 90 91 /* Access macros for `fd_set'. */ 92 #define FD_SET(fd, fdsetp) __FD_SET (fd, fdsetp) 93 #define FD_CLR(fd, fdsetp) __FD_CLR (fd, fdsetp) 94 #define FD_ISSET(fd, fdsetp) __FD_ISSET (fd, fdsetp) 95 #define FD_ZERO(fdsetp) __FD_ZERO (fdsetp) 96 97 98 __BEGIN_DECLS 99 100 /* Check the first NFDS descriptors each in READFDS (if not NULL) for read 101 readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS 102 (if not NULL) for exceptional conditions. If TIMEOUT is not NULL, time out 103 after waiting the interval specified therein. Returns the number of ready 104 descriptors, or -1 for errors. 105 106 This function is a cancellation point and therefore not marked with 107 __THROW. */ 108 extern int select (int __nfds, fd_set *__restrict __readfds, 109 fd_set *__restrict __writefds, 110 fd_set *__restrict __exceptfds, 111 struct timeval *__restrict __timeout); 112 #ifdef _LIBC 113 extern __typeof(select) __select_nocancel attribute_hidden; 114 libc_hidden_proto(select) 115 #endif 116 117 #ifdef __USE_XOPEN2K 118 /* Same as above only that the TIMEOUT value is given with higher 119 resolution and a sigmask which is been set temporarily. This version 120 should be used. 121 122 This function is a cancellation point and therefore not marked with 123 __THROW. */ 124 extern int pselect (int __nfds, fd_set *__restrict __readfds, 125 fd_set *__restrict __writefds, 126 fd_set *__restrict __exceptfds, 127 const struct timespec *__restrict __timeout, 128 const __sigset_t *__restrict __sigmask); 129 #endif 130 131 __END_DECLS 132 133 #endif /* sys/select.h */ 134