Re: [fpc-pascal] how to use procedure of object in C

[OBones]

Michael Van Canneyt wrote:

On Mon, 9 Mar 2015, Xiangrong Fang wrote:

Hi all,
I define a procedure like this:

type
  TDataHandler = procedure(data: Pointer) of object;

procedure SetHandler(h: TDataHandler); external cdecl;

Now, can I implement SetHandler in a library written in C, then call h in C?

IMHO Not without separate assembler code for each CPU.

Michael.

How about using TMethod?

procedure DataHandler(DummySelf: Pointer; data: Pointer);
begin
  // do what you want to do, DummySelf is always nil.
end;

var
  Method: TMethod;
begin
  Method.Data := nil;
  Method.Code := @DataHandler;

  SetHandler(TDataHandler(Method));
end;

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