1<poll.h>(0P)               POSIX Programmer's Manual              <poll.h>(0P)
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NAME

6       poll.h - definitions for the poll() function
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SYNOPSIS

9       #include <poll.h>
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DESCRIPTION

12       The  <poll.h> header shall define the pollfd structure that includes at
13       least the following members:
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16              int    fd       The following descriptor being polled.
17              short  events   The input event flags (see below).
18              short  revents  The output event flags (see below).
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20       The <poll.h> header shall define the following type through typedef:
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22       nfds_t An unsigned integer type used for the number  of  file  descrip‐
23              tors.
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26       The  implementation  shall support one or more programming environments
27       in which the width of nfds_t is no greater than the width of type long.
28       The  names  of these programming environments can be obtained using the
29       confstr() function or the getconf utility.
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31       The following symbolic constants shall be  defined,  zero  or  more  of
32       which  may  be  OR'ed together to form the events or revents members in
33       the pollfd structure:
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35       POLLIN Data other than high-priority data may be read without blocking.
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37       POLLRDNORM
38              Normal data may be read without blocking.
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40       POLLRDBAND
41              Priority data may be read without blocking.
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43       POLLPRI
44              High priority data may be read without blocking.
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46       POLLOUT
47              Normal data may be written without blocking.
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49       POLLWRNORM
50              Equivalent to POLLOUT.
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52       POLLWRBAND
53              Priority data may be written.
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55       POLLERR
56              An error has occurred ( revents only).
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58       POLLHUP
59              Device has been disconnected ( revents only).
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61       POLLNVAL
62              Invalid fd member ( revents only).
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65       The significance and semantics of normal, priority,  and  high-priority
66       data are file and device-specific.
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68       The  following  shall be declared as a function and may also be defined
69       as a macro. A function prototype shall be provided.
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72              int   poll(struct pollfd[], nfds_t, int);
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74       The following sections are informative.
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APPLICATION USAGE

77       None.
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RATIONALE

80       None.
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FUTURE DIRECTIONS

83       None.
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SEE ALSO

86       The  System  Interfaces  volume  of  IEEE Std 1003.1-2001,   confstr(),
87       poll(), the Shell and Utilities volume of IEEE Std 1003.1-2001, getconf
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90       Portions  of  this text are reprinted and reproduced in electronic form
91       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
92       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
93       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
94       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
95       event of any discrepancy between this version and the original IEEE and
96       The  Open Group Standard, the original IEEE and The Open Group Standard
97       is the referee document. The original Standard can be  obtained  online
98       at http://www.opengroup.org/unix/online.html .
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102IEEE/The Open Group                  2003                         <poll.h>(0P)
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