[fpc-pascal]How to make a constructor failed?

[Michael Van Canneyt]

On Thu, 22 Aug 2002, mili wrote:

> Hello, Every one
>
>   I intend to create my own class such as the following:
> >>>>
> type
>   TMyClass = class(TObject)
>     public
>       constructor Create(fn:String);
>       destructor Free;
>   end;//TMyClass
>
> implementation
>
> constructor TMyClass.Create(fn:String);
> begin
>   if not FileExists(fn) then begin
>     // ---> Here I want to make the new object nil
>   end;
> end;//TMyClass.Create
>
> demo:
>   myclass:=TMyClass.Create('aaaa.txt');
>   if myclass=nil then exit;// ---> Here I can check if the object is valid
> <<<<<<<<
>
>   Can you tell me what's the constructor should be like to implement this?

As far as I know, there is no way to do this. The best you can do is
raise an exception and catch this.

Michael.