---
name: "lio_listio"
section: "2"
platform: "linux"
package: "freebsd-manpages"
version: "6.0-5"
release: "Debian 4.0 (Etch)"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/lio_listio"
---

# lio\_listio(2)

list directed I/O (REALTIME)

## NAME

**lio\_listio** – list directed I/O (REALTIME)

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<aio.h\>**

*int*\

**lio\_listio**(*int mode*, *struct aiocb \* const \[\] list*, *int nent*, *struct sigevent \*sig*);

## DESCRIPTION

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)](/aio_read/2.md).

- LIO\_NOP

  No operation.

- LIO\_WRITE

  Write data as if by a call to [aio\_write(2)](/aio_write/2.md).

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.

## 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 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\_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)](/aio_read/2.md) and [aio\_write(2)](/aio_write/2.md).

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.md).

## SEE ALSO

[aio\_error(2)](/aio_error/2.md), [aio\_read(2)](/aio_read/2.md), [aio\_write(2)](/aio_write/2.md), [read(2)](/read/2.md), [write(2)](/write/2.md), [aio(4)](/aio/4.md)

## STANDARDS

The **lio\_listio**() function is expected to conform to IEEE Std 1003.1-2001 (“POSIX.1”).