[fpc-pascal] Mac osx callback functions parameters: wrong values in 386 mode.

fpanasiti at tiscali.it fpanasiti at tiscali.it
Mon Sep 6 17:21:46 CEST 2010


Using control callback function with a control (a button) apparently 
results in wrong 
parameter values when compiling to 386 (values are correct compiling 
to 
ppc).

The attached case refers to a callback procedure myActionProc
(lControlRef: ControlRef; PartCode: ControlPartCode) applied to a push 
button. Essentially:
- Compiling to ppc, everything is correct (in particular PartCode= 
10)
- Compiling to 386, the value of lControlRef is correct, but the 
value of PartCode is wrong (a random value)

As I  got the same results (first parameter, i.e. the ControlRef, 
correct, others wrong) with callbacks with more parameters (as the ones 
used with DataBrowser), it would seem related to different 
architecture's parameter passing modes, but I couldn't get it out.

Thanks in advance for any suggestion.

Regards
Francesco Panasiti
=============================================================
(The following code is derived from the default FPC Carbon 
Application 2.4.0 template).
unit MainUnit;
interface
procedure RunMainProcedure;
implementation
uses
    MacOSAll;
procedure RunMainProcedure;
var
    err : OSStatus;
    nibRef : IBNibRef;
    window : WindowRef;
    lRect: Rect;
var
    theControlRef: ControlRef;
    lControlActionUPP: ControlActionUPP;
procedure myActionProc (lControlRef: ControlRef; PartCode: 
ControlPartCode);
var
    lstring: string;
begin
    MoveTo(7, 280);
    Str(partCode, lstring);
    DrawString(lstring);
end;
begin
    // Create a Nib reference passing the name of the nib file 
(without the .nib extension)
    // CreateNibReference only searches into the application bundle.
    err := CreateNibReference(CFSTR('main'), nibRef);
    // Once the nib reference is created, set the menu bar. 
"MainMenu" is the name of the menu bar
    // object. This name is set in InterfaceBuilder when the nib is 
created.
    err := SetMenuBarFromNib(nibRef, CFSTR('MenuBar'));
    // Then create a window. "MainWindow" is the name of the window 
object. This name is set in
    // InterfaceBuilder when the nib is created.
    err := CreateWindowFromNib(nibRef, CFSTR('MainWindow'), window);
    SetRect(lRect, 10, 100, 110, 200);
    theControlRef := NewControl(window, lRect, 'OK', true, 0, 0, 1, 
kControlBevelButtonNormalBevelProc, 0);
    lControlActionUPP:= NewControlActionUPP(ControlActionProcPtr
(@myActionProc));
    SetControlAction(theControlRef, lControlActionUPP);
    // We don't need the nib reference anymore.
    DisposeNibReference(nibRef);
    ShowWindow(window);
    SetPort(GetWindowPort(window));
    RunApplicationEventLoop;
    Halt(byte(err));
end;
end.
=============================================================
program Start;
uses
    MainUnit;
begin
    RunMainProcedure;
end.
============================================================= 


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