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<h1 class="topictitle1"><span class="apiname">cwbDQ_AsyncRead</span></h1>
<div><div class="section"><h4 class="sectiontitle">Purpose</h4><p>Read a record from the iSeries™ data
queue object that is identified by the specified handle. The <span class="apiname">AsyncRead</span> will
return control to the caller immediately. This call is used in conjunction
with the <span class="apiname">CheckData</span> API. When a record is read from a data
queue, it is removed from the data queue. If the data queue is empty for more
than the specified wait time, the read is aborted, and the <span class="apiname">CheckData</span> API
returns a value of CWBDQ_TIMED_OUT. You may specifying a wait time from 0
to 99,999 (in seconds) or forever (-1). A wait time of zero causes the <span class="apiname">CheckData</span> API
to return a value of CWBDQ_TIMED_OUT on its initial call if there is no data
in the data queue.</p>
</div>
<div class="section"><h4 class="sectiontitle">Syntax</h4><pre>
unsigned int CWB_ENTRY cwbDQ_AsyncRead(
cwbDQ_QueueHandle queueHandle,
cwbDQ_Data data,
signed long waitTime,
cwbDQ_ReadHandle *readHandle,
cwbSV_ErrHandle errorHandle);</pre>
</div>
<div class="section"><h4 class="sectiontitle">Parameters</h4><dl><dt class="dlterm">cwbDQ_QueueHandle queueHandle - input</dt>
<dd>Handle that was returned by a previous call to the <span class="apiname">cwbDQ_Open</span> function.
This identifies the iSeries data queue object.</dd>
<dt class="dlterm">cwbDQ_Data data - input</dt>
<dd>The data object to be read from the iSeries data queue.</dd>
<dt class="dlterm">signed long waitTime - input</dt>
<dd>Length of time in seconds to wait for data, if the data queue is empty.
A wait time of -1 indicates to wait forever.</dd>
<dt class="dlterm">cwbDQ_ReadHandle * readHandle - output</dt>
<dd>Pointer to where the <span class="apiname">cwbDQ_ReadHandle</span> will be written.
This handle will be used in subsequent calls to the <span class="apiname">cwbDQ_CheckData</span> API.</dd>
<dt class="dlterm">cwbSV_ErrHandle errorHandle - output</dt>
<dd>Any returned messages will be written to this object. It is created with
the <span class="apiname">cwbSV_CreateErrHandle</span> API. The messages may be retrieved
through the <span class="apiname">cwbSV_GetErrText</span> API. If the parameter is set
to zero, no messages will be retrieved.</dd>
</dl>
</div>
<div class="section"><h4 class="sectiontitle">Return Codes</h4><p>The following list shows common return
values.</p>
<dl><dt class="dlterm">CWB_OK</dt>
<dd>Successful completion.</dd>
<dt class="dlterm">CWBDQ_INVALID_TIME</dt>
<dd>Invalid wait time.</dd>
<dt class="dlterm">CWBDQ_INVALID_QUEUE_HANDLE</dt>
<dd>Invalid queue handle.</dd>
<dt class="dlterm">CWBDQ_INVALID_SEARCH</dt>
<dd>Invalid search order.</dd>
</dl>
</div>
<div class="section"><h4 class="sectiontitle">Usage</h4><p>This function requires that you have previously
issued the following APIs: </p>
<ul><li><span class="apiname">cwbDQ_Open</span> or <span class="apiname">cwbDQ_OpenEx</span></li>
<li><span class="apiname">cwbDQ_CreateData</span></li>
</ul>
</div>
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<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="rzaikdqapilist2.htm" title="After the cwbDQ_Open API is used to create a connection to a specific data queue, these other APIs can be used to utilize it. Use the cwbDQ_Close API when the connection no longer is needed.">Data Queues: Accessing data queues APIs</a></div>
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