io_cancel(2) — Linux manual page

io_cancel(2)               System Calls Manual               io_cancel(2)

NAME         top

       io_cancel - cancel an outstanding asynchronous I/O operation

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <linux/aio_abi.h>    /* Definition of needed types */
       #include <sys/syscall.h>      /* Definition of SYS_* constants */
       #include <unistd.h>

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

DESCRIPTION         top

       Note: you probably want to use the io_getevents(3) wrapper
       function provided by libaio; see VERSIONS.

       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         top

       On success, io_cancel() returns 0.  On error, -1 is returned, and
       errno is set to indicate the error.

ERRORS         top

       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         top

       libaio ⟨https://pagure.io/libaio⟩ provides a wrapper function with
       the same name, but different prototype and return value.  You
       probably want to use that wrapper.

STANDARDS         top

       Linux.

HISTORY         top

       Linux 2.5.

SEE ALSO         top

       io_destroy(2), io_getevents(2), io_setup(2), io_submit(2),
       io_cancel(3), aio(7)

COLOPHON         top

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Linux man-pages 6.18            2026-04-11                   io_cancel(2)

Pages that refer to this page: io_destroy(2),  io_getevents(2),  io_setup(2),  io_submit(2),  syscalls(2),  aio(7)

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