NAME

       aio_cancel - cancel an outstanding asynchronous I/O request

SYNOPSIS

       #include <aio.h>

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

       Link with -lrt.

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(7)).   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.

VERSIONS

       The aio_cancel() function is available since glibc 2.1.

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008.

EXAMPLE

       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)

COLOPHON

       This page is part of release 3.54 of the Linux man-pages project.  A  description  of  the
       project,     and    information    about    reporting    bugs,    can    be    found    at
       http://www.kernel.org/doc/man-pages/.

                                            2012-05-08                              AIO_CANCEL(3)