with lazarus 0.9.28.x I get the error in the subject, while compiling the packages "cmdline" and "plotpanel" (downloaded from CCR) They were working, before my recent troubles with the packages and the installation of the .2 and .3 (daily) lazarus versions.

The error messages are:
C:\lazarus\extras\cmdline-0.5.2\cmdline\ucmdbox.pas(1834,32) Error: Can't take the address of constant expressions
and
C:\lazarus\extras\plotpanel_lazarus_0.96\plotpanel.pas(658,54) Error: Can't take the address of constant expressions
C:\lazarus\extras\plotpanel_lazarus_0.96\plotpanel.pas(771,52) Error: Can't take the address of constant expressions
C:\lazarus\extras\plotpanel_lazarus_0.96\plotpanel.pas(828,51) Error: Can't take the address of constant expressions
C:\lazarus\extras\plotpanel_lazarus_0.96\plotpanel.pas(864,52) Error: Can't take the address of constant expressions

in my opinion there are no constant expressions there.

Thanks,

Roberto

Err, it would useful for you to post the source code in question. I guess these are errors are caused by object properties?...

-Fl?vio

2010/2/5 Fl?vio Etrusco :

Err, it would useful for you to post the source code in question. I guess these are errors are caused by object properties?...

I did not post them because the files are available on the Lazarus CCR. However here is the error in the package "cmdline":

Offending instruction:              Inc(InputPos, UTF8Length(s));
where the parameters are defined as:
s: WideString;          // a local variable in the method
property InputPos: integer Read FInputPos;          // a class
property with the correspondig private FInputPos:  integer;

Roberto

That's it.
That code used to compile with FPC 2.2, but doesn't with 2.4. See: http://wiki.freepascal.org/User_Changes_2.4.0#Treating_direct-mapped_properties_as_regular_fields In this case, simply change the code to "Inc(FInputPos, UTF8Length(s));".

Best regards,
Fl?vio

Ok, thanks!
I'll patch the files on my PC, but maintainers of the components "Plot Panel" and "CmdLine" should be alerted on this.

Roberto

2010/2/5 Fl?vio Etrusco :

2010/2/5 Fl?vio Etrusco :

In this case, I can't understand why the error is gine in plotpanel package for the following line:

    FOnXMarksWrite(self,X,xStr,ACanvas.Font,evtHandled);

which is inside the implementation of

    procedure TPlotPanel.WriteXaxisValues(ACanvas:TCanvas);
    var
       X : Extended;
       XStr : string;
       evtHandled : Boolean;
    ...

isn't it right to read the ACanvas.Font property?
In fact, I can't change it to the FFont private variable, because they belong to different classes.

Roberto

What's the signature of FOnXMarksWrite method/handler?

-Fl?vio

2010/2/5 Fl?vio Etrusco :

private
    FOnXMarksWrite: TWriteAxisEvt;  // X Axis draw event
    FOnYMarksWrite: TWriteAxisEvt;  // Y Axis draw event

which refers to:

TWriteAxisEvt = procedure(Sender: TCustomPanel; Value:extended;var AxisText:String; var AxisFont:TFont; var EventHandled:boolean) of object;

bye,

Roberto

So there you go. The parameter is passed as 'var', which implies knowing the variable address. I doubt there's a valid reason for this, so the fix would be to remove the 'var' modifier.

[]s

2010/2/5 Fl?vio Etrusco :

So there you go. The parameter is passed as 'var', which implies knowing the variable address. I doubt there's a valid reason for this, so the fix would be to remove the 'var' modifier.

Thanks, that fixed it.

Roberto