This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       None.

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group  Base
       Specifications  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any discrepancy between this version and the original
       IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee  document.
       The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                        poll.h(7POSIX)

       The  <poll.h>  header  shall  define  the  pollfd  structure,  which shall include at least the following
       members:

           int    fd       The following descriptor being polled.
           short  events   The input event flags (see below).
           short  revents  The output event flags (see below).

       The <poll.h> header shall define the following type through typedef:

       nfds_t        An unsigned integer type used for the number of file descriptors.

       The implementation shall support one or more programming environments in which the width of nfds_t is  no
       greater  than  the width of type long.  The names of these programming environments can be obtained using
       the confstr() function or the getconf utility.

       The <poll.h> header shall define the following symbolic constants, zero or more of  which  may  be  OR'ed
       together to form the events or revents members in the pollfd structure:

       POLLIN        Data other than high-priority data may be read without blocking.

       POLLRDNORM    Normal data may be read without blocking.

       POLLRDBAND    Priority data may be read without blocking.

       POLLPRI       High priority data may be read without blocking.

       POLLOUT       Normal data may be written without blocking.

       POLLWRNORM    Equivalent to POLLOUT.

       POLLWRBAND    Priority data may be written.

       POLLERR       An error has occurred (revents only).

       POLLHUP       Device has been disconnected (revents only).

       POLLNVAL      Invalid fd member (revents only).

       The significance and semantics of normal, priority, and high-priority data are file and device-specific.

       The  following  shall  be declared as a function and may also be defined as a macro. A function prototype
       shall be provided.

           int   poll(struct pollfd [], nfds_t, int);

       Thefollowingsectionsareinformative.

       None.

       poll.h — definitions for the poll() function

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

       None.

       The System Interfaces volume of POSIX.1‐2017, confstr(), poll()

       The Shell and Utilities volume of POSIX.1‐2017, getconf

       #include <poll.h>