IDLE

version 3

IDLE

The IDLE command is designed only for use with the compiler. This command is only used in compiled databases in which user-defined methods are written so that no calls are made back to the 4D engine. For example, if a method has a For loop in which no 4D commands are executed, the loop could not be interrupted by a process installed with ON EVENT CALL, nor could a user switch to another application. In this case, you should insert IDLE to allow 4D to trap events. If you do not want any interruptions, omit IDLE.

In the following example, the loop would never terminate in a compiled database without the call to IDLE:

      ` Do Something Project Method
   ON EVENT CALL ("EVENT METHOD") 
   <>vbWeStop:=False 
   MESSAGE ("Processing..."+Char(13)+"Type any key to interrupt...") 
   Repeat 
         ` Do some processing that doesn't involve a 4D command
      IDLE 
   Until (<>vbWeStop)
   ON EVENT CALL ("")

with:

      ` EVENT METHOD Project Method
   If (Undefined(KeyCode))
      KeyCode:=0
   End if
   If (KeyCode#0)
      CONFIRM ("Do you really want to stop this operation?")
      If (OK=1)
         <>vbWeStop:=True
      End if
   End if

Compiler Commands, ON EVENT CALL.