io_cancel(2)

1io_cancel(2)                  System Calls Manual                 io_cancel(2)
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NAME

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

9       Standard C library (libc, -lc)
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11       Alternatively, Asynchronous I/O library (libaio, -laio); see VERSIONS.
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SYNOPSIS

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

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

34       On success, io_cancel() returns 0.  For the failure  return,  see  VER‐
35       SIONS.
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ERRORS

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

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

60       Linux.
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HISTORY

63       Linux 2.5.
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