ON TIMER block

The ON TIMER seconds clause defines a set of instructions that must be executed at regular intervals. This interaction block can be used, for example, to check if a message has arrived in a queue, and needs to be processed.

As ON TIMER can fire field input validation, it is therefore not recommended in dialogs allowing input.

The parameter of ON TIMER must be an integer literal or variable. If the value is zero, the dialog timeout is disabled.

It is not recommended to use the ON TIMER trigger with a short timeout period, such as 1 or 2 seconds. The purpose of this trigger is to give the control back to the program after a reasonable period of time, such as 10, 20 or 60 seconds.

ON TIMER 30
   CALL check_for_messages()

Important: The timer value is taken into account when the dialog initializes its internal data structures. If you use a program variable instead of an integer constant, a change of the variable has no effect if the change takes place after the dialog has initialized. If you want to change the value of the timeout variable, it must be done before the dialog block.