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IO_SETUP(2)                Linux Programmer's Manual               IO_SETUP(2)



NAME
       io_setup - create an asynchronous I/O context

SYNOPSIS
       #include <&lt;libaio.h>&gt;

       int io_setup(unsigned nr_events, aio_context_t *ctxp);

       Link with -laio.

DESCRIPTION
       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 han-
       dle.

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

ERRORS
       EAGAIN The  specified  nr_events  exceeds the user's limit of available
              events.

       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.

VERSIONS
       The  asynchronous  I/O system calls first appeared in Linux 2.5, August
       2002.

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.

       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.

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

COLOPHON
       This page is part of release 3.05 of the Linux  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



Linux                             2008-06-18                       IO_SETUP(2)