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



NAME
       io_setup - create an asynchronous I/O context

SYNOPSIS
       #include <libaio.h>

       int io_setup(unsigned nr_events, aio_context_t *ctxp);

       Link with -laio.

DESCRIPTION
       io_setup()  creates  an  asynchronous I/O context capable of receiving at least nr_events.  ctxp must not point to an AIO
       context that already exists, and must be initialized to 0 prior to the call.  On successful creation of the AIO  context,
       *ctxp is filled in with the resulting handle.

RETURN VALUE
       On success, io_setup() returns 0.  For the failure return, see NOTES.

ERRORS
       EAGAIN The specified nr_events exceeds the user's limit of available events.

       EFAULT An invalid pointer is passed for ctxp.

       EINVAL ctxp is not initialized, or the specified nr_events exceeds internal limits.  nr_events should be greater than 0.

       ENOMEM Insufficient kernel resources are available.

       ENOSYS io_setup() is not implemented on this architecture.

VERSIONS
       The asynchronous I/O system calls first appeared in Linux 2.5, August 2002.

CONFORMING TO
       io_setup() is Linux-specific and should not be used in programs that are intended to be portable.

NOTES
       Glibc does not provide a wrapper function for this system call.

       The  wrapper  provided  in libaio for io_setup() does not follow the usual C library conventions for indicating error: on
       error it returns a negated error number (the negative of one of the values listed in ERRORS).   If  the  system  call  is
       invoked  via  syscall(2), then the return value follows the usual conventions for indicating an error: -1, with errno set
       to a (positive) value that indicates the error.

SEE ALSO
       io_cancel(2), io_destroy(2), io_getevents(2), io_submit(2)

COLOPHON
       This page is part of release 3.25 of the Linux man-pages project.  A description of the project,  and  information  about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                                                      2008-06-18                                                IO_SETUP(2)