IO_SETUP(2) Linux Programmer's Manual IO_SETUP(2)
io_setup - create an asynchronous I/O context
#include <linux/aio_abi.h> /* Defines needed types */
int io_setup(unsigned nr_events, aio_context_t *ctx_idp);
Note: There is no glibc wrapper for this system call; see NOTES.
The io_setup() system call creates an asynchronous I/O context suitable
for concurrently processing nr_events operations. The ctx_idp argument
must not point to an AIO context that already exists, and must be ini-
tialized to 0 prior to the call. On successful creation of the AIO
context, *ctx_idp is filled in with the resulting handle.
On success, io_setup() returns 0. For the failure return, see NOTES.
EAGAIN The specified nr_events exceeds the user's limit of available
events, as defined in /proc/sys/fs/aio-max-nr.
EFAULT An invalid pointer is passed for ctx_idp.
EINVAL ctx_idp 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.
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. You
could invoke it using syscall(2). But instead, you probably want to
use the io_setup() wrapper function provided by libaio.
Note that the libaio wrapper function uses a different type (io_con-
text_t *) for the ctx_idp 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.
io_cancel(2), io_destroy(2), io_getevents(2), io_submit(2), aio(7)
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Linux 2017-09-15 IO_SETUP(2)
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