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, 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 * 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