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AIX Version 4.3 Base Operating System and Extensions Technical Reference, Volume 1

aio_return or aio_return64 Subroutine

Purpose

Retrieves the return status of an asynchronous I/O request.

Library

Standard C Library (libc.a)

Syntax

#include <aio.h> 
int aio_return(handle)
aio_handle_t handle;
int aio_return64(handle)
aio_handle_t handle;

Description

The aio_return subroutine retrieves the return status of the asynchronous I/O request associated with the aio_handle_t handle if the I/O request has completed. The status returned is the same as the status that would be returned by the corresponding read or write function calls. If the I/O operation has not completed, the returned status is undefined.

The aio_return64 subroutine is similar to the aio_return subroutine except that it retrieves the error status associated with an aiocb64 control block.

Parameters

handle The handle field of an aio control block (aiocb or aiocb64) structure is set by a previous call of the aio_read, aio_read64, aio_write, aio_write64, lio_listio, aio_listio64 subroutine. If a random memory location is passed in, random results are returned.

Execution Environment

The aio_return and aio_return64 subroutines can be called from the process environment only.

Return Values

The aio_return subroutine returns the status of an asynchronous I/O request corresponding to those returned by read or write functions. If the error status returned by the aio_error subroutine call is EINPROG, the value returned by the aio_return subroutine is undefined.

Examples

An aio_read request to read 1000 bytes from a disk device eventually, when the aio_error subroutine returns a 0, causes the aio_return subroutine to return 1000. An aio_read request to read 1000 bytes from a 500 byte file eventually causes the aio_return subroutine to return 500. An aio_write request to write to a read-only file system results in the aio_error subroutine eventually returning EROFS and the aio_return subroutine returning a value of -1.

Implementation Specifics

The aio_return and aio_return64 subroutines are part of Base Operating System (BOS) Runtime.

Related Information

The aio_cancel or aio_cancel64 subroutine, aio_error or aio_error64 subroutine, aio_read or aio_read64 subroutine, aio_suspend or aio_suspend64 subroutine, aio_write or aio_write64 subroutine, lio_listio or lio_listio64 subroutine.

The Asynchronous I/O Overview and the Communications I/O Subsystem: Programming Introduction in AIX Version 4.3 Kernel Extensions and Device Support Programming Concepts.

The Input and Output Handling Programmer's Overview in AIX General Programming Concepts: Writing and Debugging Programs describes the files, commands, and subroutines used for low-level, stream, terminal, and asynchronous I/O interfaces.


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