A Question on Calls to Subroutines

[Kernelpanic]

@mnrvovrfc - First it prints 4 then 8. The "test" variable inside the subprogram is "protected", of type INTEGER which is two bytes. Although there is a variable named just like it which is supposed to be accessible inside that subprogram which is twice as large.

Without STATIC declaration line the second PRINT test would give 10.

Something is unclear there. 

Call by reference:

Code: (Select All)

'A little problem  - 24. Nov. 2023



Option _Explicit



Declare Sub callthisthing (u As Long) As Long



Dim Shared test As Long



test = 4

Print " test 1  = "; test ' = 4



'Call by reference (Standard)

callthisthing test '= 1 -- First call!



'Because the procedure now receives the actual address

'of the variable and can change its value.

'The name in the procedure doesn't matter: u(test2) = 8

Print " test 2  = "; test ' = 8



Print

Print "End of my tests!"

End



Sub callthisthing (u As Long)



  Static As Integer test



  test = test + 1 ' = 1 -- (0 + 1)

  Print " Sub test = "; test



  u = u * 2

  Print " Sub u    = "; u ' = 8

End Sub

Call by value:

Code: (Select All)

'A little problem  - 24. Nov. 2023



Option _Explicit



Declare Sub callthisthing (u As Long) As Long



Dim Shared test As Long



test = 4

Print " test 1  = "; test ' = 4



'Call by value

callthisthing (test) '= 1 -- First call!

Print " test 2  = "; test ' = 4 -- Because the procedure only worked with one copy.



Print

Print "End of my tests!"

End



Sub callthisthing (u As Long)



  Static As Integer test



  test = test + 1 ' = 1 -- (0 + 1)

  Print " Sub test = "; test



  u = u * 2

  Print " Sub u    = "; u ' = 8

End Sub