NAME
lio_listio —
list directed I/O (REALTIME)
LIBRARY
library “libc”
SYNOPSIS
#include
<aio.h>
int
lio_listio(int mode,
struct aiocb * const list[], int
nent, struct sigevent *sig);
DESCRIPTION
Thelio_listio()
function initiates a list of I/O requests with a single function call. The
list argument is an array of pointers to
aiocb structures describing each operation to perform,
with nent elements. NULL
elements are ignored.
The aio_lio_opcode field of each aiocb specifies the operation to be performed. The following operations are supported:
LIO_READ- Read data as if by a call to aio_read(2).
LIO_NOP- No operation.
LIO_WRITE- Write data as if by a call to aio_write(2).
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,
sig can be used to request asynchronous notification
when all operations have completed. If sig is
NULL, no notification is sent.
For SIGEV_KEVENT notifications, the posted
kevent will contain:
| Member | Value |
| ident | list |
| filter | EVFILT_LIO |
| udata | value stored in sig->sigev_value |
For SIGEV_SIGNO and
SIGEV_THREAD_ID notifications, the information for
the queued signal will include SI_ASYNCIO in the
si_code field and the value stored in
sig->sigev_value in the
si_value field.
For SIGEV_THREAD notifications, the value
stored in sig->sigev_value is passed to the
sig->sigev_notify_function as described in
sigevent(3).
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.
RETURN VALUES
If mode is LIO_WAIT,
the lio_listio() function returns 0 if the
operations completed successfully, otherwise -1.
If mode is
LIO_NOWAIT, the lio_listio()
function returns 0 if the operations are successfully queued, otherwise
-1.
ERRORS
The lio_listio() function will fail
if:
- [
EAGAIN] - There are not enough resources to enqueue the requests.
- [
EAGAIN] - The request would cause the system-wide limit
{AIO_MAX}to be exceeded. - [
EINVAL] - The mode argument is neither
LIO_WAITnorLIO_NOWAIT, or nent is greater than{AIO_LISTIO_MAX}. - [
EINVAL] - The asynchronous notification method in sig->sigev_notify is invalid or not supported.
- [
EINTR] - A signal interrupted the system call before it could be completed.
- [
EIO] - 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
aiocb structure individually by calling
aio_error(2).
SEE ALSO
aio_error(2), aio_read(2), aio_write(2), read(2), write(2), sigevent(3), siginfo(3), aio(4)
STANDARDS
The lio_listio() function is expected to
conform to IEEE Std 1003.1-2001
(“POSIX.1”).