mirror of https://github.com/mkerrisk/man-pages
111 lines
3.0 KiB
Plaintext
111 lines
3.0 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "<poll.h>" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" <poll.h>
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.SH NAME
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poll.h \- definitions for the poll() function
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.SH SYNOPSIS
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.LP
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\fB#include <poll.h> \fP
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.SH DESCRIPTION
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.LP
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The \fI<poll.h>\fP header shall define the \fBpollfd\fP structure
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that includes at least the following members:
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.sp
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.RS
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.nf
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\fBint fd \fP The following descriptor being polled. \fB
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short events \fP The input event flags (see below). \fB
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short revents \fP The output event flags (see below). \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 \fI<poll.h>\fP header shall define the following type through
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\fBtypedef\fP:
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.TP 7
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\fBnfds_t\fP
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An unsigned integer type used for the number of file descriptors.
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.sp
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.LP
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The implementation shall support one or more programming environments
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in which the width of \fBnfds_t\fP is no greater than the
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width of type \fBlong\fP. The names of these programming environments
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can be obtained using the \fIconfstr\fP() function or the \fIgetconf\fP
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utility.
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.LP
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The following symbolic constants shall be defined, zero or more of
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which may be OR'ed together to form the \fIevents\fP or
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\fIrevents\fP members in the \fBpollfd\fP structure:
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.TP 7
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POLLIN
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Data other than high-priority data may be read without blocking.
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.TP 7
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POLLRDNORM
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Normal data may be read without blocking.
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.TP 7
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POLLRDBAND
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Priority data may be read without blocking.
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.TP 7
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POLLPRI
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High priority data may be read without blocking.
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.TP 7
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POLLOUT
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Normal data may be written without blocking.
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.TP 7
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POLLWRNORM
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Equivalent to POLLOUT.
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.TP 7
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POLLWRBAND
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Priority data may be written.
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.TP 7
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POLLERR
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An error has occurred ( \fIrevents\fP only).
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.TP 7
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POLLHUP
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Device has been disconnected ( \fIrevents\fP only).
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.TP 7
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POLLNVAL
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Invalid \fIfd\fP member ( \fIrevents\fP only).
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.sp
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.LP
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The significance and semantics of normal, priority, and high-priority
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data are file and device-specific.
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.LP
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The following shall be declared as a function and may also be defined
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as a macro. A function prototype shall be provided.
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.sp
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.RS
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.nf
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\fBint poll(struct pollfd[], nfds_t, int);
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\fP
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.fi
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.RE
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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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The System Interfaces volume of IEEE\ Std\ 1003.1-2001, \fIconfstr\fP(),
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\fIpoll\fP(), the Shell and Utilities volume of IEEE\ Std\ 1003.1-2001,
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\fIgetconf\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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