lio_listio -- list directed I/O (REALTIME)
Standard C Library (libc, -lc)
#include <aio.h>
int
lio_listio(int mode, struct aiocb * const [] list, int nent,
struct sigevent *sig);
The lio_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, 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.
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 0 if the operations are
successfully queued, otherwise -1.
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_WAIT nor LIO_NOWAIT,
or nent is greater than AIO_LISTIO_MAX.
[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).
aio_error(2), aio_read(2), aio_write(2), read(2), write(2), aio(4)
The lio_listio() function is expected to conform to IEEE Std 1003.1-2001
(``POSIX.1'').
FreeBSD 5.2.1 January 12, 2003 FreeBSD 5.2.1 [ Back ] |
