NAME¶

io_getevents - read asynchronous I/O events from the completion queue

LIBRARY¶

Standard C library (libc, -lc)

SYNOPSIS¶

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

int syscall(SYS_io_getevents, aio_context_t ctx_id,
            long min_nr, long nr, struct io_event *events,
            struct timespec *timeout);

DESCRIPTION¶

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

The io_getevents() system call attempts to read at least min_nr events and up to nr events from the completion queue of the AIO context specified by ctx_id.

The timeout argument specifies the amount of time to wait for events, and is specified as a relative timeout in a timespec(3) structure.

The specified time will be rounded up to the system clock granularity and is guaranteed not to expire early.

Specifying timeout as NULL means block indefinitely until at least min_nr events have been obtained.

RETURN VALUE¶

On success, io_getevents() returns the number of events read. This may be 0, or a value less than min_nr, if the timeout expired. It may also be a nonzero value less than min_nr, if the call was interrupted by a signal handler.

On error, -1 is returned, and errno is set to indicate the error.

ERRORS¶

EFAULT

Either events or timeout is an invalid pointer.

EINTR

Interrupted by a signal handler; see signal(7).

EINVAL

ctx_id is invalid.

EINVAL

min_nr is out of range or nr is out of range.

ENOSYS

io_getevents() is not implemented on this architecture.

VERSIONS¶

libaio provides a wrapper function with the same name, but different prototype and return value. You probably want to use that wrapper.

STANDARDS¶

Linux.

HISTORY¶

Linux 2.5.

SEE ALSO¶

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