mirror of https://github.com/mkerrisk/man-pages
116 lines
3.4 KiB
Plaintext
116 lines
3.4 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "<sys/select.h>" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" <sys/select.h>
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.SH NAME
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sys/select.h \- select types
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.SH SYNOPSIS
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.LP
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\fB#include <sys/select.h>\fP
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.SH DESCRIPTION
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.LP
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The \fI<sys/select.h>\fP header shall define the \fBtimeval\fP structure
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that includes at least the following
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members:
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.sp
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.RS
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.nf
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\fBtime_t tv_sec \fP Seconds. \fB
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suseconds_t tv_usec \fP Microseconds. \fB
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\fP
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.fi
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.RE
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.LP
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The \fBtime_t\fP and \fBsuseconds_t\fP types shall be defined as described
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in \fI<sys/types.h>\fP .
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.LP
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The \fBsigset_t\fP type shall be defined as described in \fI<signal.h>\fP
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\&.
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.LP
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The \fBtimespec\fP structure shall be defined as described in \fI<time.h>\fP
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\&.
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.LP
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The \fI<sys/select.h>\fP header shall define the \fBfd_set\fP type
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as a structure.
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.LP
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Each of the following may be declared as a function, or defined as
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a macro, or both:
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.TP 7
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\fBvoid\fP \fIFD_CLR\fP(\fBint\fP \fIfd\fP, \fBfd_set *\fP\fIfdset\fP)
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.sp
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Clears the bit for the file descriptor \fIfd\fP in the file descriptor
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set \fIfdset\fP.
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.TP 7
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\fBint\fP \fIFD_ISSET\fP(\fBint\fP \fIfd\fP, \fBfd_set *\fP\fIfdset\fP)
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.sp
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Returns a non-zero value if the bit for the file descriptor \fIfd\fP
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is set in the file descriptor set by \fIfdset\fP, and 0
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otherwise.
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.TP 7
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\fBvoid\fP \fIFD_SET\fP(\fBint\fP \fIfd\fP, \fBfd_set *\fP\fIfdset\fP)
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.sp
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Sets the bit for the file descriptor \fIfd\fP in the file descriptor
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set \fIfdset\fP.
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.TP 7
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\fBvoid\fP \fIFD_ZERO\fP(\fBfd_set *\fP\fIfdset\fP)
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.sp
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Initializes the file descriptor set \fIfdset\fP to have zero bits
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for all file descriptors.
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.sp
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.LP
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If implemented as macros, these may evaluate their arguments more
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than once, so applications should ensure that the arguments
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they supply are never expressions with side effects.
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.LP
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The following shall be defined as a macro:
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.TP 7
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FD_SETSIZE
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.sp
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Maximum number of file descriptors in an \fBfd_set\fP structure.
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.sp
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.LP
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The following shall be declared as functions and may also be defined
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as macros. Function prototypes shall be provided.
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.sp
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.RS
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.nf
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\fBint pselect(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
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const struct timespec *restrict, const sigset_t *restrict);
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int select(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
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struct timeval *restrict);
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\fP
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.fi
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.RE
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.LP
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Inclusion of the \fI<sys/select.h>\fP header may make visible all
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symbols from the headers \fI<signal.h>\fP, \fI<sys/time.h>\fP,
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and \fI<time.h>\fP.
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.LP
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\fIThe following sections are informative.\fP
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.SH APPLICATION USAGE
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.LP
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None.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fI<signal.h>\fP , \fI<sys/time.h>\fP ,
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\fI<sys/types.h>\fP , \fI<time.h>\fP , the
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System Interfaces volume of IEEE\ Std\ 1003.1-2001, \fIpselect\fP(),
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\fIselect\fP()
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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