Delphi Exception handling problem with multiple Exception handling blocks
- by Robert Oschler
I'm using Delphi Pro 6 on Windows XP with FastMM 4.92 and the JEDI JVCL 3.0. Given the code below, I'm having the following problem: only the first exception handling block gets a valid instance of E. The other blocks match properly with the class of the Exception being raised, but E is unassigned (nil).
For example, given the current order of the exception handling blocks when I raise an E1 the block for E1 matches and E is a valid object instance. However, if I try to raise an E2, that block does match, but E is unassigned (nil). If I move the E2 catching block to the top of the ordering and raise an E1, then when the E1 block matches E is is now unassigned. With this new ordering if I raise an E2, E is properly assigned when it wasn't when the E2 block was not the first block in the ordering. Note I tried this case with a bare-bones project consisting of just a single Delphi form.
Am I doing something really silly here or is something really wrong?
Thanks,
Robert
type
E1 = class(EAbort)
end;
E2 = class(EAbort)
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
try
raise E1.Create('hello');
except
On E: E1 do
begin
OutputDebugString('E1');
end;
On E: E2 do
begin
OutputDebugString('E2');
end;
On E: Exception do
begin
OutputDebugString('E(all)');
end;
end; // try()
end;
