POSIX_ASYNCHRONOUS_IO

POSIX Asynchronous I/O option. More...

Files
file	aio.h
	POSIX asynchronous I/O (<aio.h>)

Functions
int	aio_cancel (int fildes, struct aiocb *aiocbp)
	Cancel an outstanding asynchronous I/O request.
int	aio_error (const struct aiocb *aiocbp)
	Retrieve the error status of an asynchronous I/O request.
int	aio_fsync (int op, struct aiocb *aiocbp)
	Asynchronously synchronise a file's data and metadata to storage.
int	aio_read (struct aiocb *aiocbp)
	Enqueue an asynchronous read operation.
ssize_t	aio_return (struct aiocb *aiocbp)
	Retrieve the return status of a completed asynchronous I/O request.
int	aio_suspend (const struct aiocb *const list[], int nent, const struct timespec *timeout)
	Wait for one or more asynchronous I/O requests to complete.
int	aio_write (struct aiocb *aiocbp)
	Enqueue an asynchronous write operation.
int	lio_listio (int mode, struct aiocb *const list[ZRESTRICT], int nent, struct sigevent *ZRESTRICT sig)
	Initiate a list of asynchronous I/O requests.

Detailed Description

POSIX Asynchronous I/O option.

Function Documentation

aio_cancel()

int aio_cancel	(	int	fildes,
		struct aiocb *	aiocbp
	)

Cancel an outstanding asynchronous I/O request.

Parameters

fildes	File descriptor.
aiocbp	Control block to cancel, or NULL to cancel all for fildes.

Returns

AIO_CANCELED, AIO_NOTCANCELED, AIO_ALLDONE, or -1 on error.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_cancel.html

aio_error()

int aio_error

(

const struct aiocb *

aiocbp

)

Retrieve the error status of an asynchronous I/O request.

Parameters

aiocbp

Asynchronous I/O control block.

Returns

EINPROGRESS if still running, 0 on success, or a positive error number.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_error.html

aio_fsync()

int aio_fsync	(	int	op,
		struct aiocb *	aiocbp
	)

Asynchronously synchronise a file's data and metadata to storage.

Parameters

op	O_SYNC or O_DSYNC, selecting the completion guarantee.
aiocbp	Control block specifying the file descriptor.

Returns

0 if the request was successfully queued, or -1 on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_fsync.html

aio_read()

int aio_read

(

struct aiocb *

aiocbp

)

Enqueue an asynchronous read operation.

Parameters

aiocbp

Control block specifying the file, offset, buffer, and size.

Returns

0 if the request was successfully queued, or -1 on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_read.html

aio_return()

ssize_t aio_return

(

struct aiocb *

aiocbp

)

Retrieve the return status of a completed asynchronous I/O request.

Must be called exactly once after aio_error() returns a value other than EINPROGRESS. Calling it a second time yields undefined behaviour.

Parameters

aiocbp

Asynchronous I/O control block.

Returns

Number of bytes transferred on success, or -1 on error (sets errno).

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_return.html

aio_suspend()

int aio_suspend	(	const struct aiocb *const	list[],
		int	nent,
		const struct timespec *	timeout
	)

Wait for one or more asynchronous I/O requests to complete.

Parameters

list	Array of pointers to control blocks to wait on.
nent	Number of entries in list.
timeout	Maximum wait time, or NULL to block indefinitely.

Returns

0 on success, or -1 with errno set on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_suspend.html

aio_write()

int aio_write

(

struct aiocb *

aiocbp

)

Enqueue an asynchronous write operation.

Parameters

aiocbp

Control block specifying the file, offset, buffer, and size.

Returns

0 if the request was successfully queued, or -1 on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/aio_write.html

lio_listio()

int lio_listio	(	int	mode,
		struct aiocb *const	list[ZRESTRICT],
		int	nent,
		struct sigevent *ZRESTRICT	sig
	)

Initiate a list of asynchronous I/O requests.

Parameters

mode	LIO_WAIT (block until all complete) or LIO_NOWAIT (return immediately).
list	Array of control block pointers (LIO_NOP entries are skipped).
nent	Number of entries in list.
sig	Notification on completion (only for LIO_NOWAIT), or NULL.

Returns

0 on success, or -1 with errno set on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/lio_listio.html