jammy (2) io_setup.2.gz

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NAME
       io_setup - create an asynchronous I/O context


SYNOPSIS
       #include <linux/aio_abi.h>          /* Defines needed types */

       long io_setup(unsigned nr_events, aio_context_t *ctx_idp);

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


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 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.


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


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
       The asynchronous I/O system calls first appeared in Linux 2.5.


CONFORMING TO
       io_setup() is Linux-specific and should not be used in programs that are intended to be portable.


NOTES
       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_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.


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


COLOPHON
       This page is part of release 5.10 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
       https://www.kernel.org/doc/man-pages/.