4cbf380ce9
Shifting into the sign position is currently supported as a GCC extension, but explicitly subjected to future changes. Computation in the unsigned type followed by a cast to the signed type is a GCC extension that will be available forever.
134 lines
4.1 KiB
C
134 lines
4.1 KiB
C
/* `fd_set' type and related macros, and `select'/`pselect' declarations.
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Copyright (C) 1996-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/* POSIX 1003.1g: 6.2 Select from File Descriptor Sets <sys/select.h> */
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#ifndef _SYS_SELECT_H
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#define _SYS_SELECT_H 1
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#include <features.h>
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/* Get definition of needed basic types. */
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#include <bits/types.h>
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/* Get __FD_* definitions. */
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#include <bits/select.h>
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/* Get __sigset_t. */
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#include <bits/sigset.h>
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#ifndef __sigset_t_defined
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# define __sigset_t_defined
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typedef __sigset_t sigset_t;
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#endif
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/* Get definition of timer specification structures. */
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#define __need_time_t
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#define __need_timespec
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#include <time.h>
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#define __need_timeval
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#include <bits/time.h>
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#ifndef __suseconds_t_defined
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typedef __suseconds_t suseconds_t;
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# define __suseconds_t_defined
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#endif
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/* The fd_set member is required to be an array of longs. */
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typedef long int __fd_mask;
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/* Some versions of <linux/posix_types.h> define this macros. */
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#undef __NFDBITS
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/* It's easier to assume 8-bit bytes than to get CHAR_BIT. */
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#define __NFDBITS (8 * (int) sizeof (__fd_mask))
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#define __FD_ELT(d) ((d) / __NFDBITS)
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#define __FD_MASK(d) ((__fd_mask) (1UL << ((d) % __NFDBITS)))
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/* fd_set for select and pselect. */
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typedef struct
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{
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/* XPG4.2 requires this member name. Otherwise avoid the name
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from the global namespace. */
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#ifdef __USE_XOPEN
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__fd_mask fds_bits[__FD_SETSIZE / __NFDBITS];
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# define __FDS_BITS(set) ((set)->fds_bits)
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#else
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__fd_mask __fds_bits[__FD_SETSIZE / __NFDBITS];
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# define __FDS_BITS(set) ((set)->__fds_bits)
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#endif
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} fd_set;
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/* Maximum number of file descriptors in `fd_set'. */
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#define FD_SETSIZE __FD_SETSIZE
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#ifdef __USE_MISC
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/* Sometimes the fd_set member is assumed to have this type. */
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typedef __fd_mask fd_mask;
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/* Number of bits per word of `fd_set' (some code assumes this is 32). */
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# define NFDBITS __NFDBITS
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#endif
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/* Access macros for `fd_set'. */
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#define FD_SET(fd, fdsetp) __FD_SET (fd, fdsetp)
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#define FD_CLR(fd, fdsetp) __FD_CLR (fd, fdsetp)
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#define FD_ISSET(fd, fdsetp) __FD_ISSET (fd, fdsetp)
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#define FD_ZERO(fdsetp) __FD_ZERO (fdsetp)
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__BEGIN_DECLS
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/* Check the first NFDS descriptors each in READFDS (if not NULL) for read
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readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
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(if not NULL) for exceptional conditions. If TIMEOUT is not NULL, time out
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after waiting the interval specified therein. Returns the number of ready
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descriptors, or -1 for errors.
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This function is a cancellation point and therefore not marked with
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__THROW. */
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extern int select (int __nfds, fd_set *__restrict __readfds,
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fd_set *__restrict __writefds,
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fd_set *__restrict __exceptfds,
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struct timeval *__restrict __timeout);
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#ifdef __USE_XOPEN2K
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/* Same as above only that the TIMEOUT value is given with higher
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resolution and a sigmask which is been set temporarily. This version
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should be used.
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This function is a cancellation point and therefore not marked with
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__THROW. */
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extern int pselect (int __nfds, fd_set *__restrict __readfds,
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fd_set *__restrict __writefds,
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fd_set *__restrict __exceptfds,
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const struct timespec *__restrict __timeout,
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const __sigset_t *__restrict __sigmask);
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#endif
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/* Define some inlines helping to catch common problems. */
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#if __USE_FORTIFY_LEVEL > 0 && defined __GNUC__
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# include <bits/select2.h>
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#endif
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__END_DECLS
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#endif /* sys/select.h */
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