Hamlet081299
asked on
WARNING: Passing 0 length variant arrays may be hazardous to your health!!!
I found an interesting quirk in Delphi (v5).
The following piece of code causes a rather nasty access violation if Args is of 0 length.
---
function Y(const Name: String; const Args: array of variant): variant;
begin
Result := Length(Args);
end;
function X(const Name: String; Args: array of variant): variant;
begin
Result := Y(Name, Args);
end;
procedure TForm1.Button1Click(Sender
var
Args: array of variant;
ret: variant;
begin
SetLength(Args, 0);
ret := X('test', Args);
ShowMessage(ret);
end;
---
This is just a warning to those who may be interested. The solution is quite simple make Args in function X be "const Args: ..." (like in Y)
However I still contend that the code is perfectly valid.
If someone thinks that my code is flawed (rather than Delphi that is) then I may be willing to dish out some points.
;-)
The following piece of code causes a rather nasty access violation if Args is of 0 length.
---
function Y(const Name: String; const Args: array of variant): variant;
begin
Result := Length(Args);
end;
function X(const Name: String; Args: array of variant): variant;
begin
Result := Y(Name, Args);
end;
procedure TForm1.Button1Click(Sender
var
Args: array of variant;
ret: variant;
begin
SetLength(Args, 0);
ret := X('test', Args);
ShowMessage(ret);
end;
---
This is just a warning to those who may be interested. The solution is quite simple make Args in function X be "const Args: ..." (like in Y)
However I still contend that the code is perfectly valid.
If someone thinks that my code is flawed (rather than Delphi that is) then I may be willing to dish out some points.
;-)
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P.S: I think I did submit a bug report for this already after D4 came out...
ASKER
Sorry there's no points on this one, but I thought it better to have an accepted answer rather than delete the question, so that people may refer to it.