??? [OMCSessionZMQ] allways check for errors

needs additional changes to OMCSession* and ModelicaSystem

Author: syntron

OMPython/OMCSession.py

@@ -556,6 +556,8 @@ def sendExpression(self, command, parsed=True):
         if p is not None:
             raise OMCSessionException("Process Exited, No connection with OMC. Create a new instance of OMCSessionZMQ!")
 
+        logger.debug("sendExpression(%r, %r)", command, parsed)
+
         attempts = 0
         while True:
             try:
@@ -576,6 +578,14 @@ def sendExpression(self, command, parsed=True):
             return None
         else:
             result = self._omc.recv_string()
+
+            # allways check for error
+            self._omc.send_string("getErrorString()", flags=zmq.NOBLOCK)
+            error_raw = self._omc.recv_string()
+            error_str = om_parser_typed(error_raw)
+            if error_str:
+                raise OMCSessionException(f"OM Error for 'sendExpression({command}, {parsed})': {error_str}")
+
             if parsed is True:
                 answer = om_parser_typed(result)
                 return answer