poll.h(0P)                POSIX Programmer's Manual               poll.h(0P)

PROLOG         top

       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.

NAME         top

       poll.h — definitions for the poll() function

SYNOPSIS         top

       #include <poll.h>

DESCRIPTION         top

       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

       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

       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);

       The following sections are informative.



RATIONALE         top




SEE ALSO         top

       The System Interfaces volume of POSIX.1‐2008, confstr(3p), poll(3p)

       The Shell and Utilities volume of POSIX.1‐2008, getconf(1p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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 .

       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 .

IEEE/The Open Group                 2013                          poll.h(0P)