io_setup(2)                   System Calls Manual                  io_setup(2)

NAME
       io_setup - create an asynchronous I/O context

LIBRARY
       Standard C library (libc, -lc)

       Alternatively, Asynchronous I/O library (libaio, -laio); see VERSIONS.

SYNOPSIS
       #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 VERSIONS.

DESCRIPTION
       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 VERSIONS.

       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.

RETURN VALUE
       On success, io_setup() returns 0.  For the failure return, see
       VERSIONS.

ERRORS
       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.

VERSIONS
       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.

STANDARDS
       Linux.

HISTORY
       Linux 2.5.

SEE ALSO
       io_cancel(2), io_destroy(2), io_getevents(2), io_submit(2), aio(7)

Linux man-pages 6.7               2023-10-31                       io_setup(2)