debian man page for io_queue_init

io_queue_init(2)						     Linux AIO							  io_queue_init(2)

NAME
       io_queue_init - Initialize asynchronous io state machine

SYNOPSIS
       #include <errno.h>

       #include <libaio.h>

       int io_queue_init(int maxevents, io_context_t *ctx);

DESCRIPTION
       io_queue_init  Attempts	to  create  an	aio context capable of receiving at least maxevents events.  ctx must point to an aio context that
       already exists and must be initialized to 0 before the call.  If the operation is successful, *cxtp is filled with the resulting handle.

RETURN VALUES
       On success, io_queue_init returns 0.  Otherwise, -error is return, where error is one of the Exxx values defined in the Errors section.

ERRORS
       EFAULT iocbs referenced data outside of the program's accessible address space.

       EINVAL maxevents is <= 0 or ctx is an invalid memory location.

       ENOSYS Not implemented.

       EAGAIN maxevents > max_aio_reqs where max_aio_reqs is a tunable value.

SEE ALSO
       io(3),  io_cancel(3),   io_fsync(3),   io_getevents(3),	 io_prep_fsync(3),   io_prep_pread(3),	 io_prep_pwrite(3),   io_queue_release(3),
       io_queue_run(3), io_queue_wait(3), io_set_callback(3), io_submit(3), errno(3).

Linux 2.4							    2009-06-10							  io_queue_init(2)