DESCRIPTION

epoll_create() creates an epoll "instance", requesting the kernel to allocate an event backing store dimensioned for size descriptors. The size is not the maximum size of the backing store but just a hint to the kernel about how to dimension internal structures. (Nowadays, size is ignored; see NOTES below.)

epoll_create() returns a file descriptor referring to the new epoll instance. This file descriptor is used for all the subsequent calls to the epoll interface. When no longer required, the file descriptor returned by epoll_create() should be closed by using close(2). When all file descriptors referring to an epoll instance have been closed, the kernel destroys the instance and releases the associated resources for reuse.

If flags is 0, then, other than the fact that the obsolete size argument is dropped, epoll_create1() is the same as epoll_create(). The following value can be included in flags to obtain different behavior:

RETURN VALUE

On success, these system calls return a nonnegative file descriptor. On error, −1 is returned, and errno is set to indicate the error.

ERRORS

CONFORMING TO

epoll_create() is Linux-specific, and was introduced in kernel 2.5.44.

NOTES

Since Linux 2.6.8, the size argument is unused. (The kernel dynamically sizes the required data structures without needing this initial hint.)

SEE ALSO

close(2), epoll_ctl(2), epoll_wait(2), epoll(7)