io_cancel(2)

1IO_CANCEL(2)               Linux Programmer's Manual              IO_CANCEL(2)
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NAME

6       io_cancel - cancel an outstanding asynchronous I/O operation
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SYNOPSIS

9       #include <linux/aio_abi.h>    /* Definition of needed types */
10       #include <sys/syscall.h>      /* Definition of SYS_* constants */
11       #include <unistd.h>
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13       int syscall(SYS_io_cancel, aio_context_t ctx_id, struct iocb *iocb,
14                   struct io_event *result);
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DESCRIPTION

17       Note:  this  page  describes  the raw Linux system call interface.  The
18       wrapper function provided by libaio  uses  a  different  type  for  the
19       ctx_id argument.  See NOTES.
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21       The  io_cancel() system call attempts to cancel an asynchronous I/O op‐
22       eration previously submitted with io_submit(2).  The iocb argument  de‐
23       scribes the operation to be canceled and the ctx_id argument is the AIO
24       context to which the operation was submitted.  If the operation is suc‐
25       cessfully canceled, the event will be copied into the memory pointed to
26       by result without being placed into the completion queue.
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RETURN VALUE

29       On success, io_cancel() returns 0.  For the failure return, see NOTES.
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ERRORS

32       EAGAIN The iocb specified was not canceled.
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34       EFAULT One of the data structures points to invalid data.
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36       EINVAL The AIO context specified by ctx_id is invalid.
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38       ENOSYS io_cancel() is not implemented on this architecture.
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VERSIONS

41       The asynchronous I/O system calls first appeared in Linux 2.5.
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CONFORMING TO

44       io_cancel() is Linux-specific and should not be used in  programs  that
45       are intended to be portable.
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NOTES

48       You  probably  want to use the io_cancel() wrapper function provided by
49       libaio.
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51       Note that the libaio wrapper function uses a  different  type  (io_con‐
52       text_t)  for  the  ctx_id  argument.  Note also that the libaio wrapper
53       does not follow the usual C library conventions for indicating  errors:
54       on  error it returns a negated error number (the negative of one of the
55       values  listed  in  ERRORS).   If  the  system  call  is  invoked   via
56       syscall(2), then the return value follows the usual conventions for in‐
57       dicating an error: -1, with errno set to a (positive) value that  indi‐
58       cates the error.
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COLOPHON

64       This  page  is  part of release 5.12 of the Linux man-pages project.  A
65       description of the project, information about reporting bugs,  and  the
66       latest     version     of     this    page,    can    be    found    at
67       https://www.kernel.org/doc/man-pages/.
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71Linux                             2021-03-22                      IO_CANCEL(2)