The CtAPI has been designed to be called from external applications. This API has not been designed to be called from the Citect SCADA Cicode DLL functions or from a Citect SCADA protocol driver. Calling the CtAPI from Cicode DLL functions or a Citect SCADA protocol driver may cause a deadlock condition to occur. This will result in Citect SCADA and the protocol driver hanging. If you need to call the CtAPI from a protocol driver, you need to create a new Win32 thread to call the API. You cannot call the CtAPI from the Cicode DLL interface.
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Published June 2018