NAME

       aio_cancel - cancel an outstanding asynchronous I/O request

LIBRARY

       Real-time library (librt, -lrt)

SYNOPSIS

       #include <aio.h>

       int aio_cancel(int fd, struct aiocb *aiocbp);

DESCRIPTION

       The  aio_cancel()  function  attempts  to  cancel  outstanding  asynchronous  I/O  requests  for the file
       descriptor fd.  If aiocbp is NULL, all such requests are canceled.  Otherwise, only the request described
       by  the  control  block  pointed  to  by  aiocbp is canceled.  (See aio(7) for a description of the aiocb
       structure.)

       Normal asynchronous notification occurs for canceled requests  (see  aio(7)  and  sigevent(3type)).   The
       request return status (aio_return(3)) is set to -1, and the request error status (aio_error(3)) is set to
       ECANCELED.  The control block of requests that cannot be canceled is not changed.

       If the request could not be canceled, then it will terminate in the usual way after  performing  the  I/O
       operation.  (In this case, aio_error(3) will return the status EINPROGRESSS.)

       If  aiocbp is not NULL, and fd differs from the file descriptor with which the asynchronous operation was
       initiated, unspecified results occur.

       Which operations are cancelable is implementation-defined.

RETURN VALUE

       The aio_cancel() function returns one of the following values:

       AIO_CANCELED
              All requests were successfully canceled.

       AIO_NOTCANCELED
              At least one of the requests specified was not canceled because it was in progress.  In this case,
              one may check the status of individual requests using aio_error(3).

       AIO_ALLDONE
              All requests had already been completed before the call.

       -1     An error occurred.  The cause of the error can be found by inspecting errno.

ERRORS

       EBADF  fd is not a valid file descriptor.

       ENOSYS aio_cancel() is not implemented.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌──────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │Interface                                                                     │ Attribute     │ Value   │
       ├──────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │aio_cancel()                                                                  │ Thread safety │ MT-Safe │
       └──────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

       POSIX.1-2008.

HISTORY

       glibc 2.1.  POSIX.1-2001.

EXAMPLES

       See aio(7).

SEE ALSO

       aio_error(3),  aio_fsync(3),  aio_read(3),  aio_return(3),  aio_suspend(3),  aio_write(3), lio_listio(3),
       aio(7)