EPOLL_WAIT(3C) Standard C Library Functions EPOLL_WAIT(3C)


NAME


epoll_wait, epoll_pwait - wait for epoll events

SYNOPSIS


#include <sys/epoll.h>

int epoll_wait(int epfd, struct epoll_event *events,
int maxevents, int timeout);


int epoll_pwait(int epfd, struct epoll_event *events,
int maxevents, int timeout,
const sigset_t *sigmask);


DESCRIPTION


The epoll_wait() function waits for events on the epoll(5) instance
specified by epfd. The events parameter must point to an array of
maxevents epoll_event structures to be filled in with pending events.
The timeout argument specifies the number of milliseconds to wait for an
event if none is pending. A timeout of -1 denotes an infinite timeout.

The epoll_pwait() is similar to epoll_wait(), but takes an additional
sigmask argument that specifies the desired signal mask when
epoll_pwait() is blocked. It is equivalent to atomically setting the
signal mask, calling epoll_wait(), and restoring the signal mask upon
return, and is therefore similar to the relationship between select(3C)
and pselect(3C).


RETURN VALUES


Upon successful completion, epoll_wait() and epoll_pwait() return the
number of events, or 0 if none was pending and timeout milliseconds
elapsed. If an error occurs, -1 is returned and errno is set to indicate
the error.


ERRORS


The epoll_wait() and epoll_pwait() functions will fail if:

EBADF
epfd is not a valid file descriptor.


EFAULT
The memory associated with events was not mapped or was not
writable.


EINTR
A signal was received during the epoll_wait() or epoll_pwait().


EINVAL
Either epfd is not a valid epoll(5) instance or maxevents is
not greater than zero.


NOTES


The epoll(5) facility is implemented for purposes of offering
compatibility for Linux-borne applications; native applications should
continue to prefer using event ports via the port_create(3C),
port_associate(3C) and port_get(3C) interfaces. See epoll(5) for
compatibility details and restrictions.


SEE ALSO


epoll_create(3C), epoll_ctl(3C), port_create(3C), port_associate(3C),
port_get(3C), pselect(3C), epoll(5)


April 17, 2014 EPOLL_WAIT(3C)