$UnPost
$UnPost 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
$UnPost(ECB-number)
Where:
ECB-number is a numeric value from one to the NECBS 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.
Usage
Use the $UnPost function to unpost a specified, numbered ECB. An ECB must be unposted before another post or wait on this ECB takes place. The $Post and $Wait 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.
Use the $Post, $UnPost, and $Wait functions to coordinate processing between threads for numbered ECBs. For the extended quiesce ECB, QZSIG, only the $Wait and $Post functions are valid.
$UnPost does not reset the contents of the post code or string data set by the $Post or $EcbDSet functions for the specified ECB.
Note: Even in a non-multiprocessing environment, the $UnPost 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 $Post function is issued.
The following return codes apply to the $UnPost function:
| Return code | Meaning |
|---|---|
| 0 | Success |
| 2 | Bad argument specified |
| 3 | NECBS parameter is not specified or is zero |
| 4 | The first argument is less than one or greater than the NECBS parameter |
| 5 | NUSERS = 1 |
| 8 | No argument specified |
| 12 | Invalid argument CPQZ or invalid argument following QZSIG |
See also
The ECB-related $functions are: