Delphi Compiler Error
E2009 Incompatible types – ‘%s’
Reason for the Error & Solution
The compiler has detected a difference between the declaration and use of a procedure.
program Produce;
type
ProcedureParm0 = procedure; stdcall;
ProcedureParm1 = procedure(VAR x : Integer);
procedure WrongConvention; register;
begin
end;
procedure WrongParms(x, y, z : Integer);
begin
end;
procedure TakesParm0(p : ProcedureParm0);
begin
end;
procedure TakesParm1(p : ProcedureParm1);
begin
end;
begin
TakesParm0(WrongConvention);
TakesParm1(WrongParms);
end.
The call of ‘TakesParm0’ will elicit an error because the type ‘ProcedureParm0’ expects a ‘stdcall’ procedure, whereas ‘WrongConvention’ is declared with the ‘register’ calling convention. Similarly, the call of ‘TakesParm1’ will fail because the parameter lists do not match.
program Solve;
type
ProcedureParm0 = procedure; stdcall;
ProcedureParm1 = procedure(VAR x : Integer);
procedure RightConvention; stdcall;
begin
end;
procedure RightParms(VAR x : Integer);
begin
end;
procedure TakesParm0(p : ProcedureParm0);
begin
end;
procedure TakesParm1(p : ProcedureParm1);
begin
end;
begin
TakesParm0(RightConvention);
TakesParm1(RightParms);
end.
The solution to both of these problems is to ensure that the calling convention or the parameter lists matches the declaration.
