#include <libaio.h>
int io_cancel(aio_context_t ctx_id, struct iocb *iocb,
struct io_event *result);
Link with -laio.
io_cancel() attempts to cancel an asynchronous I/O operation previously submitted with io_submit(2). ctx_id is the AIO context ID of the operation to be canceled. If the AIO context is found, the event will be canceled and then copied into the memory pointed to by result without being placed into the completion queue.
The asynchronous I/O system calls first appeared in Linux 2.5, August 2002.
io_cancel() is Linux-specific and should not be used in programs that are intended to be portable.
The wrapper provided in libaio for io_cancel() does not follow the usual C library conventions for indicating error: 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.