epoll_create(2) 맨 페이지 - 윈디하나의 솔라나라

개요

섹션
맨 페이지 이름
검색(S)

epoll_create(2)

EPOLL_CREATE(2)            Linux Programmer's Manual           EPOLL_CREATE(2)

NAME
       epoll_create, epoll_create1 - open an epoll file descriptor

SYNOPSIS
       #include <sys/epoll.h>

       int epoll_create(int size);
       int epoll_create1(int flags);

DESCRIPTION
       epoll_create() creates a new epoll(7) instance.  Since Linux 2.6.8, the
       size  argument is ignored, but must be greater than zero; see NOTES be‐
       low.

       epoll_create() returns a file descriptor referring to the new epoll in‐
       stance.  This file descriptor is used for all the subsequent  calls  to
       the  epoll interface.  When no longer required, the file descriptor re‐
       turned 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.

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

       EPOLL_CLOEXEC
              Set the close-on-exec (FD_CLOEXEC) flag on the new file descrip‐
              tor.   See  the description of the O_CLOEXEC flag in open(2) for
              reasons why this may be useful.

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
       EINVAL size is not positive.

       EINVAL (epoll_create1()) Invalid value specified in flags.

       EMFILE The  per-user  limit on the number of epoll instances imposed by
              /proc/sys/fs/epoll/max_user_instances  was   encountered.    See
              epoll(7) for further details.

       EMFILE The per-process limit on the number of open file descriptors has
              been reached.

       ENFILE The system-wide limit on the total number of open files has been
              reached.

       ENOMEM There was insufficient memory to create the kernel object.

VERSIONS
       epoll_create() was added to the kernel in version 2.6.  Library support
       is provided in glibc starting with version 2.3.2.

       epoll_create1()  was  added  to  the kernel in version 2.6.27.  Library
       support is provided in glibc starting with version 2.9.

CONFORMING TO
       epoll_create() is Linux-specific.

NOTES
       In the initial epoll_create() implementation,  the  size  argument  in‐
       formed the kernel of the number of file descriptors that the caller ex‐
       pected  to add to the epoll instance.  The kernel used this information
       as a hint for the amount of space to  initially  allocate  in  internal
       data structures describing events.  (If necessary, the kernel would al‐
       locate  more  space  if  the  caller's usage exceeded the hint given in
       size.)  Nowadays, this hint is no longer required (the  kernel  dynami‐
       cally sizes the required data structures without needing the hint), but
       size  must still be greater than zero, in order to ensure backward com‐
       patibility when new epoll applications are run on older kernels.

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

COLOPHON
       This page is part of release 5.02 of the Linux  man-pages  project.   A
       description  of  the project, information about reporting bugs, and the
       latest    version    of    this    page,    can     be     found     at
       https://www.kernel.org/doc/man-pages/.

Linux                             2017-09-15                   EPOLL_CREATE(2)
맨 페이지 내용의 저작권은 맨 페이지 작성자에게 있습니다.
RSS ATOM XHTML 5 CSS3