Test semaphore

Test semaphore ( semaphore ) : Boolean

Description​

The Test semaphore command tests for the existence of a semaphore.

The difference between the Semaphore function and the Test semaphore function is that Test semaphore doesn’t create the semaphore if it doesn’t exist. If the semaphore exists, the function returns True. Otherwise, it returns False.

Example​

The following example allows you to know the state of a process (in our case, while modifying the code) without modifying semaphore:

 $Win:=Open window(x1;x2;y1;y2;-Palette window)
 Repeat
  If(Test semaphore("Encrypting code"))
    POSITION MESSAGE($x3;$y3)
    MESSAGE("Encrypting code being modified.")
  Else
    POSITION MESSAGE($x3;$y3)
    MESSAGE("Modification of the encrypting code authorized.")
  End if
 Until(StopInfo)
 CLOSE WINDOW

See also​

CLEAR SEMAPHORE
Semaphore

Properties​