− cancel an outstanding asynchronous I/O request
aio_cancel(int fd, struct aiocb
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.)
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
aiocbp is not NULL, and fd differs from the
file descriptor with which the asynchronous operation was
initiated, unspecified results occur.
operations are cancelable is implementation-defined.
aio_cancel() function returns one of the following
All requests were successfully
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
All requests had already been
completed before the call.
An error occurred. The cause of the error can be found
by inspecting errno.
fd is not a valid file
aio_cancel() is not implemented.
aio_cancel() function is available since glibc
explanation of the terms used in this section, see
aio_write(3), lio_listio(3), aio(7)
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