1poll.h(0P)                 POSIX Programmer's Manual                poll.h(0P)
2
3
4

PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
10

NAME

12       poll.h — definitions for the poll() function
13

SYNOPSIS

15       #include <poll.h>
16

DESCRIPTION

18       The <poll.h> header shall define  the  pollfd  structure,  which  shall
19       include at least the following members:
20
21
22           int    fd       The following descriptor being polled.
23           short  events   The input event flags (see below).
24           short  revents  The output event flags (see below).
25
26       The <poll.h> header shall define the following type through typedef:
27
28       nfds_t        An  unsigned  integer  type  used  for the number of file
29                     descriptors.
30
31       The implementation shall support one or more  programming  environments
32       in which the width of nfds_t is no greater than the width of type long.
33       The names of these programming environments can be obtained  using  the
34       confstr() function or the getconf utility.
35
36       The <poll.h> header shall define the following symbolic constants, zero
37       or more of which may be OR'ed together to form the  events  or  revents
38       members in the pollfd structure:
39
40       POLLIN        Data  other  than  high-priority data may be read without
41                     blocking.
42
43       POLLRDNORM    Normal data may be read without blocking.
44
45       POLLRDBAND    Priority data may be read without blocking.
46
47       POLLPRI       High priority data may be read without blocking.
48
49       POLLOUT       Normal data may be written without blocking.
50
51       POLLWRNORM    Equivalent to POLLOUT.
52
53       POLLWRBAND    Priority data may be written.
54
55       POLLERR       An error has occurred (revents only).
56
57       POLLHUP       Device has been disconnected (revents only).
58
59       POLLNVAL      Invalid fd member (revents only).
60
61       The significance and semantics of normal, priority,  and  high-priority
62       data are file and device-specific.
63
64       The  following  shall be declared as a function and may also be defined
65       as a macro. A function prototype shall be provided.
66
67
68           int   poll(struct pollfd [], nfds_t, int);
69
70       The following sections are informative.
71

APPLICATION USAGE

73       None.
74

RATIONALE

76       None.
77

FUTURE DIRECTIONS

79       None.
80

SEE ALSO

82       The System Interfaces volume of POSIX.1‐2017, confstr(), poll()
83
84       The Shell and Utilities volume of POSIX.1‐2017, getconf
85

87       Portions of this text are reprinted and reproduced in  electronic  form
88       from  IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
89       table Operating System Interface (POSIX), The Open Group Base  Specifi‐
90       cations  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of
91       Electrical and Electronics Engineers, Inc and The Open Group.   In  the
92       event of any discrepancy between this version and the original IEEE and
93       The Open Group Standard, the original IEEE and The Open Group  Standard
94       is  the  referee document. The original Standard can be obtained online
95       at http://www.opengroup.org/unix/online.html .
96
97       Any typographical or formatting errors that appear  in  this  page  are
98       most likely to have been introduced during the conversion of the source
99       files to man page format. To report such errors,  see  https://www.ker‐
100       nel.org/doc/man-pages/reporting_bugs.html .
101
102
103
104IEEE/The Open Group                  2017                           poll.h(0P)
Impressum