The aio_return or aio_return64 subroutine includes information for the POSIX AIO aio_return subroutine (as defined in the IEEE std 1003.1-2001), and the Legacy AIO aio_return subroutine.
POSIX AIO aio_return Subroutine
Retrieves the return status of an asynchronous I/O operation.
Standard C Library (libc.a)
#include <aio.h> size_t aio_return (aiocbp); struct aiocb *aiocbp;
The aio_return subroutine returns the return status associated with the aiocb structure. The return status for an asynchronous I/O operation is the value that would be returned by the corresponding read, write, or fsync subroutine call. If the error status for the operation is equal to EINPROGRESS, the return status for the operation is undefined. The aio_return subroutine can be called once to retrieve the return status of a given asynchronous operation. After that, if the same aiocb structure is used in a call to aio_return or aio_error, an error may be returned. When the aiocb structure referred to by aiocbp is used to submit another asynchronous operation, the aio_return subroutine can be successfully used to retrieve the return status of that operation.
| aiocbp | Points to the aiocb structure associated with the I/O operation. |
The aiocb structure is defined in the /usr/include/aio.h file and contains the following members:
int aio_fildes off_t aio_offset char *aio_buf size_t aio_nbytes int aio_reqprio struct sigevent aio_sigevent int aio_lio_opcode
The aio_return and aio_return64 subroutines can be called from the process environment only.
If the asynchronous I/O operation has completed, the return status (as described for the read, write, and fsync subroutines) is returned. If the asynchronous I/O operation has not yet completed, the results of the aio_return subroutine are undefined.
| EINVAL | The aiocbp parameter does not refer to an asynchronous operation whose return status has not yet been retrieved. |
aio_cancel or aio_cancel64 Subroutine, aio_error or aio_error64 Subroutine, lio_listio or lio_listio64 Subroutine, aio_read or aio_read64 Subroutine, aio_suspend or aio_suspend64 Subroutine, aio_write or aio_write64 Subroutine, close Subroutine, exec: execl, execle, execlp, execv, execve, execvp, or exect Subroutine, exit, atexit, _exit, or _Exit Subroutine, fork, f_fork, or vfork Subroutine, and lseek, llseek or lseek64 Subroutine.
The read, readx, readv, readvx, or pread Subroutine in AIX 5L Version 5.2 Technical Reference: Base Operating System and Extensions Volume 2.
Legacy AIO aio_return Subroutine
Retrieves the return status of an asynchronous I/O request.
Standard C Library (libc.a)
#include <aio.h>
int aio_return( handle)
aio_handle_t handle;
int aio_return64( handle)
aio_handle_t handle;
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.
#define _AIO_AIX_SOURCE #include <sys/aio.h>or, on the command line when compiling enter:
->xlc ... -D_AIO_AIX_SOURCE ... legacy_aio_program.c
The aiocb structure is defined in the /usr/include/aio.h file and contains the following members:
int aio_whence off_t aio_offset char *aio_buf size_t aio_nbytes int aio_reqprio struct event aio_event struct osigevent aio_event int aio_flag aiohandle_t aio_handle
The aio_return and aio_return64 subroutines can be called from the process environment only.
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.
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.
The aio_cancel or aio_cancel64 (aio_cancel or aio_cancel64 Subroutine) subroutine, aio_error or aio_error64 (aio_error or aio_error64 Subroutine) subroutine, aio_read or aio_read64 (aio_read or aio_read64 Subroutine) subroutine, aio_suspend or aio_suspend64 (aio_suspend or aio_suspend64 Subroutine) subroutine, aio_write or aio_write64 (aio_write or aio_write64 Subroutine) subroutine, lio_listio or lio_listio64 (lio_listio or lio_listio64 Subroutine) subroutine.
The Asynchronous I/O Overview and the Communications I/O Subsystem: Programming Introduction in AIX 5L Version 5.2 Kernel Extensions and Device Support Programming Concepts.
The Input and Output Handling Programmer's Overview in AIX 5L Version 5.2 General Programming Concepts: Writing and Debugging Programs describes the files, commands, and subroutines used for low-level, stream, terminal, and asynchronous I/O interfaces.