NAME    [Toc]    [Back]

       aio_return  -  Returns  the  status of an asynchronous I/O
       operation (P1003.1b)

SYNOPSIS    [Toc]    [Back]

       #include <aio.h>

       ssize_t aio_return (struct aiocb *aiocbp);

LIBRARY    [Toc]    [Back]

       Asynchronous I/O Library (libaio, libaio_raw)

PARAMETERS    [Toc]    [Back]

       A pointer to the address of the aiocb structure.

DESCRIPTION    [Toc]    [Back]

       The aio_return function returns the number of  bytes  read
       or written by the corresponding asynchronous I/O function.
       The return status for an asynchronous I/O operation is the
       value  that  would  be  returned by the corresponding synchronous
  read,  write,  or  fsync  function   call.   The
       aio_error  function  returns the error status for an asynchronous
 I/O operation.

       The aio_error function returns the error status associated
       with  the  specified  aiocbp.  If  the  aio_error function
       returns anything but  EINPROGRESS,  the  asynchronous  I/O
       operation  is  complete. When the operation is complete, a
       call to the aio_return function shows if the operation  is
       successful.

       When you call the aio_return function, the aiocb structure
       is marked for reuse, thus destroying your ability to reuse
       the   structure   for  that  particular  asynchronous  I/O
       request. To avoid losing data, use the aio_error  function
       to  poll  for  completion  before  you call the aio_return
       function. Then use the aio_return function to retrieve the
       number  of  bytes  read or written during the asynchronous
       I/O operation.

       If you do not call the aio_return function, the  structure
       is  not marked for reuse. In this situation, the number of
       asynchronous I/O operations  available  for  use  in  your
       application  is  reduced  by one for every completed asynchronous
 I/O operation that does not return data through a
       call to the aio_return function.

RETURN VALUES    [Toc]    [Back]

       If  the asynchronous I/O operation has completed, then the
       return value is any of the return values normally  associated
  with  a  synchronous  read, write, or fsync function
       (the number of bytes transferred  or  -1).  If  the  asynchronous
  I/O operation has not yet completed, the results
       of aio_return are undefined.  On an unsuccessful call, the
       value  of  -1 is returned and errno is set to indicate the
       error.

ERRORS    [Toc]    [Back]

       The aio_return function fails under the  following  conditions:
  The  aiocbp  argument  does  not refer to an asynchronous
 operation whose return status has  not  yet  been
       retrieved.

SEE ALSO    [Toc]    [Back]

       Functions: close(2), exec(2), _exit(2), fork(2), lseek(2),
       read(2),    write(2),     aio_cancel(3),     aio_error(3),
       aio_group_completion_np(3),                   aio_read(3),
       aio_results_np(3), aio_suspend(3), aio_write(3),  lio_listio(3)

       Guide to Realtime Programming



                                                    aio_return(3)