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aio_return(3)
NAME
  aio_return - Returns the status of an asynchronous I/O operation (P1003.1b)

SYNOPSIS
  #include <aio.h>

  ssize_t aio_return (struct
  aiocb *aiocbp);

LIBRARY
  Asynchronous I/O Library (libaio, libaio_raw)

PARAMETERS
  *aiocbp
      A pointer to the address of the aiocb structure.

DESCRIPTION
  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
  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
  The aio_return function fails under the following conditions:

  [EINVAL]
      The aiocbp argument does not refer to an asynchronous operation whose
      return status has not yet been retrieved.

SEE ALSO
  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

Index for Section 3

Alphabetical listing for A

Top of page