io_setup - create an asynchronous I/O context
int io_setup(unsigned nr_events, aio_context_t *ctxp);
Link with -laio.
io_setup() creates an asynchronous I/O context capable of receiving at
least nr_events. ctxp must not point to an AIO context that already
exists, and must be initialized to 0 prior to the call. On successful
creation of the AIO context, *ctxp is filled in with the resulting
On success, io_setup() returns 0. For the failure return, see NOTES.
EAGAIN The specified nr_events exceeds the user’s limit of available
EFAULT An invalid pointer is passed for ctxp.
EINVAL ctxp is not initialized, or the specified nr_events exceeds
internal limits. nr_events should be greater than 0.
ENOMEM Insufficient kernel resources are available.
ENOSYS io_setup() is not implemented on this architecture.
The asynchronous I/O system calls first appeared in Linux 2.5, August
io_setup() is Linux-specific and should not be used in programs that
are intended to be portable.
Glibc does not provide a wrapper function for this system call.
The wrapper provided in libaio for io_setup() 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.
io_cancel(2), io_destroy(2), io_getevents(2), io_submit(2)
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