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 */

       long io_setup(unsigned int nr_events, aio_context_t *ctx_idp);

       Note: There is no glibc wrapper for this system call; see NOTES.

       Note: this page describes the raw Linux system call interface.  The
       wrapper function provided by libaio uses a different type for the ctx_idp
       argument.  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
       initialized 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 limit of available events, as
              defined in /proc/sys/fs/aio-max-nr (see proc(5)).

       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 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_context_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)

       This page is part of release 5.11 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at

Linux                              2021-03-22                        IO_SETUP(2)