io_setup(2)

1IO_SETUP(2)                Linux Programmer's Manual               IO_SETUP(2)
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NAME

6       io_setup - create an asynchronous I/O context
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SYNOPSIS

9       #include <libaio.h>
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11       int io_setup(unsigned nr_events, aio_context_t *ctxp);
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13       Link with -laio.
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DESCRIPTION

16       io_setup()  creates an asynchronous I/O context capable of receiving at
17       least nr_events.  ctxp must not point to an AIO  context  that  already
18       exists,  and must be initialized to 0 prior to the call.  On successful
19       creation of the AIO context, *ctxp is filled in with the resulting han‐
20       dle.
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RETURN VALUE

23       On success, io_setup() returns 0.  For the failure return, see NOTES.
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ERRORS

26       EAGAIN The  specified  nr_events  exceeds the user's limit of available
27              events.
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29       EFAULT An invalid pointer is passed for ctxp.
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31       EINVAL ctxp is not initialized,  or  the  specified  nr_events  exceeds
32              internal limits.  nr_events should be greater than 0.
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34       ENOMEM Insufficient kernel resources are available.
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36       ENOSYS io_setup() is not implemented on this architecture.
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VERSIONS

39       The  asynchronous  I/O system calls first appeared in Linux 2.5, August
40       2002.
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CONFORMING TO

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

47       Glibc does not provide a wrapper function for this system call.
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49       The wrapper provided in libaio for io_setup() does not follow the usual
50       C library conventions for indicating  error:  on  error  it  returns  a
51       negated  error  number  (the  negative  of  one of the values listed in
52       ERRORS).  If the system call is invoked via syscall(2), then the return
53       value  follows  the usual conventions for indicating an error: -1, with
54       errno set to a (positive) value that indicates the error.
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COLOPHON

60       This page is part of release 3.25 of the Linux  man-pages  project.   A
61       description  of  the project, and information about reporting bugs, can
62       be found at http://www.kernel.org/doc/man-pages/.
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66Linux                             2008-06-18                       IO_SETUP(2)