NAME

       io_setup - create an asynchronous I/O context

SYNOPSIS

       #include <linux/aio_abi.h>          /* Defines needed types */

       int io_setup(unsigned nr_events, aio_context_t *ctx_idp);

       Note: There is no glibc wrapper for this system call; see NOTES.

DESCRIPTION

       The  io_setup()  system  call  creates  an  asynchronous I/O context suitable for concurrently processing
       nr_events operations.  The ctx_idp argument 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, *ctx_idp 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,   as   defined   in
              /proc/sys/fs/aio-max-nr.

       EFAULT An invalid pointer is passed for ctx_idp.

       EINVAL ctx_idp  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.

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.  You could invoke  it  using  syscall(2).
       But instead, you probably want to use the io_setup() wrapper function provided by libaio.

       Note  that  the  libaio wrapper function uses a different type (io_context_t *) for the ctx_idp argument.
       Note also that the libaio wrapper does not follow the usual C library conventions for indicating  errors:
       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  4.04  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
       http://www.kernel.org/doc/man-pages/.