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66 lines
1.7 KiB
Plaintext
66 lines
1.7 KiB
Plaintext
.TH io_cancel 2 2002-09-03 "Linux 2.4" "Linux AIO"
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.SH NAME
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io_cancel \- Cancel io requests
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.SH SYNOPSIS
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.nf
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.B #include <errno.h>
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.sp
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.br
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.B #include <libaio.h>
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.sp
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.br
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.BI "int io_cancel(io_context_t ctx, struct iocb *iocb)"
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.br
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.sp
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struct iocb {
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void *data; /* Return in the io completion event */
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unsigned key; /* For use in identifying io requests */
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short aio_lio_opcode;
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short aio_reqprio; /* Not used */
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int aio_fildes;
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};
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.fi
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.SH DESCRIPTION
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Attempts to cancel an iocb previously passed to io_submit. If
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the operation is successfully cancelled, the resulting event is
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copied into the memory pointed to by result without being placed
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into the completion queue.
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.PP
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When one or more requests are asynchronously processed, it might be
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useful in some situations to cancel a selected operation, e.g., if it
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becomes obvious that the written data is no longer accurate and would
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have to be overwritten soon. As an example, assume an application, which
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writes data in files in a situation where new incoming data would have
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to be written in a file which will be updated by an enqueued request.
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.SH "RETURN VALUES"
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0 is returned on success , otherwise returns Errno.
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.SH ERRORS
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.TP
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.B EFAULT
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If any of the data structures pointed to are invalid.
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.TP
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.B EINVAL
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If aio_context specified by ctx_id is
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invalid.
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.TP
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.B EAGAIN
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If the iocb specified was not
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cancelled.
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.TP
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.B ENOSYS
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if not implemented.
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.SH "SEE ALSO"
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.BR io(3),
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.BR io_fsync(3),
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.BR io_getevents(3),
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.BR io_prep_fsync(3),
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.BR io_prep_pread(3),
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.BR io_prep_pwrite(3),
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.BR io_queue_init(3),
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.BR io_queue_release(3),
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.BR io_queue_run(3),
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.BR io_queue_wait(3),
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.BR io_set_callback(3),
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.BR io_submit(3),
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.BR errno(3)
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