Function as a parameter to a Function

[Joe Speroni]

Is there a mechanism in PB DLL to pass a function's address
as a parameter to another function. The following code
shows the idea of what I'd like to do. It can be accomplished
other ways, but just thought I'd ask for future reference.
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#COMPILE EXE
#REGISTER NONE
$INCLUDE "WIN32API.INC"

FUNCTION F1() AS LONG
MSGBOX "F1"
END FUNCTION

FUNCTION F2() AS LONG
MSGBOX "F2"
END FUNCTION

FUNCTION FF(BYVAL PName AS FUNCTION PTR)
CALL @PName()
END FUNCTION

FUNCTION PBMAIN() AS LONG
CALL FF(F1)
CALL FF(F2)
END FUNCTION

[Dave Navarro]

Pointers (any pointer) are simply DWORD's. So simply pass a DWORD by value and call it using CALL DWORD.

--Dave


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PowerBASIC Support
mailto:[email protected][email protected]</A>

[Semen Matusovski]

Joe --
It's enough easy (see CALL DWORD in HLP):

   #Compile Exe
   #Register None
   Declare Function MyFunc () As Double
   Function F1() As Double: Function = 5.23#: End Function
   Function F2() As Double: Function = 7.18#: End Function
   Function FF(PName As Dword) As Double
      Call Dword PName Using MyFunc() To lResult#: Function = lResult#
   End Function
   Function PbMain() As Long
      MsgBox Str$(FF(CodePtr(F1)) + FF (CodePtr(F2)))
   End Function

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[Joe Speroni]

Thanks guys. The manual needs work. It was not possible to get
to the information via use of its description of function
parameters, or the index. The old PB DOS manual was great,
particularly "See Also" for related subjects. In this case if
VARPTR had a "See Also" reference to CODEPTR I'm sure I'f have
figured it out without bothering the forum with such a simple
question.

Still I understand that it is difficult to make a manual for
all possible users with differing skill levels. PB DLL is
a great product!

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