/**

@defgroup io OTF2 I/O recording
@{

@page otf2_known_io_paradigms Known @otf2 I/O paradigms
@seclabel{otf2_known_io_paradigms}

The introduction of I/O recording with OTF2 made it necessary to distinguish
different I/O paradigms. Like it is done with the parallel paradigms, like MPI, OpenMP.
Though instead of the usual enum used to identify the paradigm, the I/O paradigms
are expressed in a dynamic way with the help of a definition record. While this
has the advantage that the API does not need to be changed only to add new
I/O paradigms, it also lacks confidence in the definition. To overcome this, OTF2
textually defines known I/O paradigms and their expected definition.

<dl>

<dt>
 @anchor POSIX
 <em>"POSIX"</em>
</dt>
<dd>
  This is the I/O interface of the @emph{POSIX standard}.

  @par Required properties
  <dl>
    <dt>Class</dt><dd>@eref{OTF2_IO_PARADIGM_CLASS_SERIAL}</dd>
    <dt>Flags</dt><dd>@eref{OTF2_IO_PARADIGM_FLAG_OS}</dd>
  </dl>
</dd>

<dt>
 @anchor ISOC
 <em>"ISOC"</em>
</dt>
<dd>
  This is the I/O interface of the @emph{ISO C standard}.

  @par Required properties
  <dl>
    <dt>Class</dt><dd>@eref{OTF2_IO_PARADIGM_CLASS_SERIAL}</dd>
  </dl>
</dd>

<dt>
 @anchor MPI-IO
 <em>"MPI-IO"</em>
</dt>
<dd>
  This is the I/O interface of the @emph{Message Passing Interface}.

  @par Required properties
  <dl>
    <dt>Class</dt><dd>@eref{OTF2_IO_PARADIGM_CLASS_PARALLEL}</dd>
    <dt>Flags</dt><dd>@eref{OTF2_IO_PARADIGM_FLAG_NONE}</dd>
  </dl>
</dd>

<dt>
 @anchor netCDF
 <em>"netCDF"</em>
</dt>
<dd>
  This is the @emph{Network Common Data Form}. The <em>class</em> depends
  on whether the NetCDF library was built with or without MPI support.

  @par Required properties
  <dl>
    <dt>Class</dt><dd>@eref{OTF2_IO_PARADIGM_CLASS_SERIAL} or @eref{OTF2_IO_PARADIGM_CLASS_PARALLEL}</dd>
    <dt>Flags</dt><dd>@eref{OTF2_IO_PARADIGM_FLAG_NONE}</dd>
  </dl>
</dd>

<dt>
 @anchor PnetCDF
 <em>"PnetCDF"</em>
</dt>
<dd>
  This is the @emph{Parallel netCDF}.

  @par Required properties
  <dl>
    <dt>Class</dt><dd>@eref{OTF2_IO_PARADIGM_CLASS_PARALLEL}</dd>
    <dt>Flags</dt><dd>@eref{OTF2_IO_PARADIGM_FLAG_NONE}</dd>
  </dl>
</dd>

<dt>
 @anchor HDF5
 <em>"HDF5"</em>
</dt>
<dd>
  This is the I/O interface of @emph{The HDF Group}. The <em>class</em> depends
  on whether the HDF5 library was built with or without MPI support.

  @par Required properties
  <dl>
    <dt>Class</dt><dd>@eref{OTF2_IO_PARADIGM_CLASS_SERIAL} or @eref{OTF2_IO_PARADIGM_CLASS_PARALLEL}</dd>
    <dt>Flags</dt><dd>@eref{OTF2_IO_PARADIGM_FLAG_NONE}</dd>
  </dl>
</dd>

<dt>
 @anchor ADIOS
 <em>"ADIOS"</em>
</dt>
<dd>
  This is the @emph{Adaptable IO System}.

  @par Required properties
  <dl>
    <dt>Class</dt><dd>@eref{OTF2_IO_PARADIGM_CLASS_PARALLEL}</dd>
    <dt>Flags</dt><dd>@eref{OTF2_IO_PARADIGM_FLAG_NONE}</dd>
  </dl>
</dd>

</dl>

@page otf2_io_operation_event_order Event order for I/O operation records
@seclabel{otf2_io_operation_event_order}

These diagrams show valid event orders of I/O operations, which also denotes
the lifetime of the (@eref{IoHandle}, @p matchingId) tuple.

If the @eref{OTF2_IO_OPERATION_FLAG_NON_BLOCKING} is not set in the @eref{IoOperationBegin}
record, then the event order must follow:

@dot
digraph otf2_io_operation_event_order_blocking {
    rankdir = LR;
    bgcolor = "transparent";
    edge [
        fontname=FreeSans,
        splines=curved
    ];
    _start [
        shape=none,
        label=""
    ];
    _end [
        shape=none,
        label=""
    ];
    node [
        shape=rect,
        style=rounded,
        fontname=FreeSans
    ];

    IoOperationBegin [
        href="@ref IoOperationBegin"
    ];
    IoOperationComplete [
        href="@ref IoOperationComplete"
    ];

    _start -> IoOperationBegin;
    IoOperationBegin -> IoOperationComplete;
    IoOperationComplete -> _end;
}
@enddot

If the @eref{OTF2_IO_OPERATION_FLAG_NON_BLOCKING} is set in the @eref{IoOperationBegin}
record, then the event order must follow:

@dot
digraph otf2_io_operation_event_order_nonblocking {
    rankdir = LR;
    bgcolor = "transparent";
    edge [
        fontname=FreeSans,
        splines=curved
    ];
    _start [
        shape=none,
        label=""
    ];
    _end0 [
        shape=none,
        label=""
    ];
    _end1 [
        shape=none,
        label=""
    ];
    node [
        shape=rect,
        style=rounded,
        fontname=FreeSans
    ];


    IoOperationBegin [
        href="@ref IoOperationBegin"
    ];
    IoOperationIssued [
        href="@ref IoOperationIssued"
    ];
    IoOperationTest [
        href="@ref IoOperationTest"
    ];
    IoOperationComplete [
        href="@ref IoOperationComplete"
    ];
    IoOperationCancelled [
        href="@ref IoOperationCancelled"
    ];

    _start -> IoOperationBegin;

    IoOperationBegin -> IoOperationIssued;

    IoOperationIssued -> IoOperationTest;
    IoOperationIssued -> IoOperationComplete;
    IoOperationIssued -> IoOperationCancelled;

    IoOperationTest -> IoOperationTest;
    IoOperationTest -> IoOperationComplete;
    IoOperationTest -> IoOperationCancelled;

    IoOperationComplete -> _end0;
    IoOperationCancelled -> _end1;
}
@enddot

@}

*/