UPDATE( | MESS | O_MESS | VAR | O_VAR | );It is used to pass the values of fields from a message in process to the corresponding field variables or, alternatively the actual values of the field variables to the corresponding fields of the message in process. The argument indicates what has to be updated.
This procedure can be used only in nodes that process messages code of I, G, R, L, D, E type, general nodes and associate instructions of GLIDER instructions that processes messages.
Example:
Inspect (G) Continue :: IF pH > 4 THEN SENDTO(Continue) ELSE BEGIN Acid := TRUE; UPDATE(MESS); END;While the EL of Inspect is searching, the messages with pH > 4 are sent to the EL of the Continue node. The others are left in the EL of Inspect after putting their Acid field to TRUE. Without the UPDATE the field Acid is not changed.