If the mode argument is LIO_WAIT, lio_listio does not return until all the requested operations have been completed. If mode is LIO_NOWAIT, the requests are processed asynchronously, and the signal specified by sig is sent when all operations have completed. If sig is NULL, the calling process is not notified of I/O completion.
The order in which the requests are carried out is not specified; in particular, there is no guarantee that they will be executed in the order 0, 1, ..., nent -1.
There are not enough resources to enqueue the requests.
The request would cause the system-wide limit AIO_MAX to be exceeded.
The mode argument is neither LIO_WAIT nor LIO_NOWAIT, or nent is greater than AIO_LISTIO_MAX.
A signal interrupted the system call before it could be completed.
One or more requests failed.
In addition, the lio_listio function may fail for any of the reasons listed for aio_read(2) and aio_write(2).
If lio_listio succeeds, or fails with an error code of EAGAIN, EINTR, or EIO, some of the requests may have been initiated. The caller should check the error status of each .Vt aiocb structure individually by calling aio_error(2).