+++ /dev/null
-.\"
-.\" epoll by Davide Libenzi ( efficient event notification retrieval )
-.\" Copyright (C) 2003 Davide Libenzi
-.\"
-.\" This program is free software; you can redistribute it and/or modify
-.\" it under the terms of the GNU General Public License as published by
-.\" the Free Software Foundation; either version 2 of the License, or
-.\" (at your option) any later version.
-.\"
-.\" This program is distributed in the hope that it will be useful,
-.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
-.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-.\" GNU General Public License for more details.
-.\"
-.\" You should have received a copy of the GNU General Public License
-.\" along with this program; if not, write to the Free Software
-.\" Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-.\"
-.\" Davide Libenzi <davidel@xmailserver.org>
-.\"
-.TH EPOLL_CTL 2 2009-01-17 "Linux" "Linux Programmer's Manual"
-.SH NAME
-epoll_ctl \- control interface for an epoll descriptor
-.SH SYNOPSIS
-.B #include <sys/epoll.h>
-.sp
-.BI "int epoll_ctl(int " epfd ", int " op ", int " fd \
-", struct epoll_event *" event );
-.SH DESCRIPTION
-This system call performs control operations on the epoll instance
-referred to by the file descriptor
-.IR epfd .
-It requests that the operation
-.I op
-be performed on the target file descriptor,
-.IR fd .
-The
-.I event
-describes the object linked to the file descriptor
-.IR fd .
-The
-.I struct epoll_event
-is defined as :
-.sp
-.in +4n
-.nf
-typedef union epoll_data {
- void *ptr;
- int fd;
- __uint32_t u32;
- __uint64_t u64;
-} epoll_data_t;
-
-struct epoll_event {
- __uint32_t events; /* Epoll events */
- epoll_data_t data; /* User data variable */
-};
-.fi
-.in
-
-The
-.I events
-member is a bit set composed using the following available event
-types:
-.TP
-.B EPOLLIN
-The associated file is available for
-.BR read (2)
-operations.
-.TP
-.B EPOLLOUT
-The associated file is available for
-.BR write (2)
-operations.
-.TP
-.BR EPOLLRDHUP " (since Linux 2.6.17)"
-Stream socket peer closed connection,
-or shut down writing half of connection.
-(This flag is especially useful for writing simple code to detect
-peer shutdown when using Edge Triggered monitoring.)
-.TP
-.B EPOLLPRI
-There is urgent data available for
-.BR read (2)
-operations.
-.TP
-.B EPOLLERR
-Error condition happened on the associated file descriptor.
-.BR epoll_wait (2)
-will always wait for this event; it is not necessary to set it in
-.IR events .
-.TP
-.B EPOLLHUP
-Hang up happened on the associated file descriptor.
-.BR epoll_wait (2)
-will always wait for this event; it is not necessary to set it in
-.IR events .
-.TP
-.B EPOLLET
-Sets the Edge Triggered behavior for the associated file descriptor.
-The default behavior for
-.B epoll
-is Level Triggered.
-See
-.BR epoll (7)
-for more detailed information about Edge and Level Triggered event
-distribution architectures.
-.TP
-.BR EPOLLONESHOT " (since Linux 2.6.2)"
-Sets the one-shot behavior for the associated file descriptor.
-This means that after an event is pulled out with
-.BR epoll_wait (2)
-the associated file descriptor is internally disabled and no other events
-will be reported by the
-.B epoll
-interface.
-The user must call
-.BR epoll_ctl ()
-with
-.B EPOLL_CTL_MOD
-to re-register the file descriptor with a new event mask.
-.PP
-The
-.B epoll
-interface supports all file descriptors that support
-.BR poll (2).
-Valid values for the
-.I op
-argument are :
-.RS
-.TP
-.B EPOLL_CTL_ADD
-Register the target file descriptor
-.I fd
-on the
-.B epoll
-instance referred to by the file descriptor
-.I epfd
-and associate the event
-.I event
-with the internal file linked to
-.IR fd .
-.TP
-.B EPOLL_CTL_MOD
-Change the event
-.I event
-associated with the target file descriptor
-.IR fd .
-.TP
-.B EPOLL_CTL_DEL
-Remove (deregister) the target file descriptor
-.I fd
-from the
-.B epoll
-instance referred to by
-.IR epfd .
-The
-.I event
-is ignored and can be NULL (but see BUGS below).
-.RE
-.SH "RETURN VALUE"
-When successful,
-.BR epoll_ctl ()
-returns zero.
-When an error occurs,
-.BR epoll_ctl ()
-returns \-1 and
-.I errno
-is set appropriately.
-.SH ERRORS
-.TP
-.B EBADF
-.I epfd
-or
-.I fd
-is not a valid file descriptor.
-.TP
-.B EEXIST
-.I op
-was
-.BR EPOLL_CTL_ADD ,
-and the supplied file descriptor
-.I fd
-is already registered with this epoll instance.
-.TP
-.B EINVAL
-.I epfd
-is not an
-.B epoll
-file descriptor,
-or
-.I fd
-is the same as
-.IR epfd ,
-or the requested operation
-.I op
-is not supported by this interface.
-.TP
-.B ENOENT
-.I op
-was
-.B EPOLL_CTL_MOD
-or
-.BR EPOLL_CTL_DEL ,
-and
-.I fd
-is not registered on with this epoll instance.
-.TP
-.B ENOMEM
-There was insufficient memory to handle the requested
-.I op
-control operation.
-.TP
-.B EPERM
-The target file
-.I fd
-does not support
-.BR epoll .
-.SH CONFORMING TO
-.BR epoll_ctl ()
-is Linux-specific, and was introduced in kernel 2.5.44.
-.\" The interface should be finalized by Linux kernel 2.5.66.
-.SH BUGS
-In kernel versions before 2.6.9, the
-.B EPOLL_CTL_DEL
-operation required a non-NULL pointer in
-.IR event ,
-even though this argument is ignored.
-Since Linux 2.6.9,
-.I event
-can be specified as NULL
-when using
-.BR EPOLL_CTL_DEL .
-Applications that need to be portable to kernels before 2.6.9
-should specify a non-NULL pointer in
-.IR event .
-.SH "SEE ALSO"
-.BR epoll_create (2),
-.BR epoll_wait (2),
-.BR poll (2),
-.BR epoll (7)
projects / thirdparty / man-pages.git / blobdiff