View source for $UnPost

<var>$UnPost</var> resets a specified Event Control Block (ECB) to an unposted state, meaning that the event has not yet occurred or has not recurred. Resets the post code to zero.

==Syntax==
<p class="syntax">$UnPost(<span class="term">ECB-number</span>)
</p>
<p>
Where:</p>
<p>
<var class="term">ECB-number</var> is a numeric value from one to the <var>NECBS</var> parameter that identifies the ECB to be unposted. The ECB number can be expressed as a numeric literal, a literal enclosed in quotation marks, a %variable, or a field name.</p>

==Usage==
<p>
Use the <var>$UnPost</var> function to unpost a specified, numbered ECB. An ECB must be unposted before another post or wait on this ECB takes place. The <var>$Post</var> and <var>$Wait</var> functions do not unpost an ECB, so that a subsequent wait on the same ECB cannot take place, because the ECB is still posted from the previous posting. </p>
<p>Use the <var>$Post</var>, <var>$UnPost</var>, and <var>$Wait</var> functions to coordinate processing between threads for numbered ECBs. For the extended quiesce ECB, QZSIG, only the <var>$Wait</var> and <var>$Post</var> functions are valid.</p>
<p>
<var>$UnPost</var> does not reset the contents of the post code or string data set by the <var>$Post</var> or <var>$EcbDSet</var> functions for the specified ECB.</p>
<p class="note"><b>Note:</b> Even in a non-multiprocessing environment, the <var>$UnPost</var> function should be used with extreme care. Unposting an ECB while users are waiting on it may keep users in a wait state forever or until the next <var>$Post</var> function is issued.</p>
<p>
The following return codes apply to the <var>$UnPost</var> function:</p>
<table>
<tr class="head">
<th>Return code </th>
<th>Meaning</th>
</tr>

<tr>
<td>0 </td>
<td>Success</td>
</tr>

<tr>
<td>2 </td>
<td>Bad argument specified</td>
</tr>

<tr>
<td>3</td>
<td>NECBS parameter is not specified or is zero</td>
</tr>

<tr>
<td>4 </td>
<td>The first argument is less than one or greater than the NECBS parameter</td>
</tr>

<tr>
<td align="right">5 </td>
<td>NUSERS = 1</td>
</tr>

<tr>
<td>8 </td>
<td>No argument specified</td>
</tr>

<tr>
<td>12</td>
<td>Invalid argument CPQZ or invalid argument following QZSIG</td>
</tr>
</table>

==See also==
The ECB-related $functions are:
<ul>
<li><var>[[$EcbDGet]]</var>
<li><var>[[$EcbDSet]]</var>
<li><var>[[$EcbTest|$EcbTest]]</var>
<li><var>[[$Post]]</var>
<li><var>[[$UnPost]]</var>
<li><var>[[$Wait]]</var>
</ul>

[[Category:SOUL $functions]]