POLL.H(7) Miscellaneous Information Manual POLL.H(7)

NAME

poll.h — definitions for the poll() function

SYNOPSIS

#include <poll.h>

DESCRIPTION

The <poll.h> header defines the pollfd structure that includes at least the following member:

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

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

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

The following symbolic constants are defined, zero or more of which may be OR-ed together to form the events or revents members in the pollfd structure:

POLLIN: Same effect as POLLRDNORM | POLLRDBAND.
POLLRDNORM: Data on priority band 0 may be read.
POLLRDBAND: Data on priority bands greater than 0 may be read.
POLLPRI: High priority data may be read.
POLLOUT: Same value as POLLWRNORM.
POLLWRNORM: Data on priority band 0 may be written.
POLLWRBAND: Data on priority bands greater than 0 may be written. This event only examines bands that have been written to at least once.
POLLERR: An error has occurred ( revents only).
POLLHUP: Device has been disconnected ( revents only).
POLLNVAL: Invalid fd member ( revents only).

The < poll.h > header declares the following function which may also be defined as a macro. Function prototypes must be provided for use with an ISO C compiler. int poll(struct pollfd[], nfds_t, int);

APPLICATION USAGE

None.

FUTURE DIRECTIONS