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), aio(7)

COLOPHON
This page is part of release 3.38 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/.