Initialize static variables?

[matthew180]

Greetings,

Is it possible to initialize static variables? If so, what is the syntax. If not, are static variables guaranteed to be set to an initial value, like zero?

This is what I'd like to be able to do:

Code: Select all

Procedure something()
  Static a.l = 0 ; Initial value.

...

EndProcedure

Matthew

[tinman]

All variables are set to zero by default. However, it would be nice to be able to initialise static ones to something else.

[Froggerprogger]

You could do it this way:

Code: Select all

Procedure MyProc()
  Static a.l, b.l, c.l
  Static isInitialized.l
  
  If isInitialized = 0
    a             = 992
    b             = 12*a
    c             = 111
    isInitialized = 1
  EndIf
  
  ; some code
  
EndProcedure

[NoahPhense]

Nice..

- np

[matthew180]

You could do it this way:

Code: Select all

Procedure MyProc()
  Static a.l, b.l, c.l
  Static isInitialized.l
  
  If isInitialized = 0
    a             = 992
    b             = 12*a
    c             = 111
    isInitialized = 1
  EndIf
  
  ; some code
  
EndProcedure

Correct, I can do that if I know for certain that PB sets up all static vars to zero. If not, the first time the function is called the values for all static vars (including isInitialized) would be undefined. A simple test such as the code you present might indicate that statics are set to zero, but this would only be an assumption until Fred says otherwise... And I can't rely on an assumption. Static vars being set to zero (or "" in the case of strings) is not documented, thus subject to change at any time.

Also, not being able to set those values at compile time means that the isInitialized check has to be performed every time the function is called and is unnecessary overhead.

Matthew

[Pupil]

Static vars are initialized to zero like all other variables in PB, just look at the commented ASM output!