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

NAME

     io_cancel - cancel an outstanding asynchronous I/O operation

SYNOPSIS

     #include <linux/aio_abi.h>          /* Defines needed types */

     int io_cancel(aio_context_t ctx_id, struct iocb *iocb,
                   struct io_event *result);

     Note: There is no glibc wrapper for this system call; see NOTES.

DESCRIPTION

     The  io_cancel()  system  call  attempts  to cancel an asynchronous I/O
     operation previously submitted with io_submit(2).   The  iocb  argument
     describes  the  operation to be canceled and the ctx_id argument is the
     AIO context to which the operation was submitted.  If the operation  is
     successfully canceled, the event will be copied into the memory pointed
     to by result without being placed into the completion queue.

RETURN VALUE

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

ERRORS

     EAGAIN The iocb specified was not canceled.

     EFAULT One of the data structures points to invalid data.

     EINVAL The AIO context specified by ctx_id is invalid.

     ENOSYS io_cancel() is not implemented on this architecture.

VERSIONS

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

CONFORMING TO

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

NOTES

     Glibc does not provide a wrapper function for this  system  call.   You
     could  invoke  it  using syscall(2).  But instead, you probably want to
     use the io_cancel() wrapper function provided by libaio.

     Note that the libaio wrapper function uses a  different  type  (io_con-
     text_t)  for  the  ctx_id  argument.  Note also that the libaio wrapper
     does not follow the usual C library conventions for indicating  errors:
     on  error it returns a negated error number (the negative of one of the
     values  listed  in  ERRORS).   If  the  system  call  is  invoked   via
     syscall(2),  then  the  return  value follows the usual conventions for
     indicating an error: -1, with errno set  to  a  (positive)  value  that
     indicates the error.