Delphi -- Casting an integer to a typed pointer?

Question

I'm having some trouble with the syntax of Delphi.

I have a record:

type
  TMyType = record
    ....
  end;

and a procedure:

procedure Foo(bar:Integer);
var
  ptr : ^TMyType
begin
  ptr := bar //how to do this?
end;

How do I properly cast an integer to a pointer of TMyType?

David Heffernan · Accepted Answer · 2011-10-18 18:38:57Z

7

Like this:

type
  PMyType = ^TMyType;

procedure Foo(bar: Integer);
var
  ptr: PMyType;
begin
  ptr := PMyType(bar);
end;

answered Oct 18, 2011 at 16:29

David Heffernan

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10 Comments

Ah I wasn't for sure a new type would be required. I figured it was like C where "typecasts" are purely optional

@Earlz typecasts aren't optional in C. You would need to cast to assign an integer to a pointer variable in C.

Pascal object is a strongly typed language, so casts are mandatory between different types.

@TridenT C is strongly typed too. And in fact C and Delphi are similar in the way that any pointer is assignment compatible with void*/Pointer.

Do note that this will fail on Win64 because there the pointer type is 64-bit and integer is still 32-bit

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TridenT · Accepted Answer · 2011-10-18 16:39:28Z

3

You must cast it explicitely with the new type:

  type PMyType = ^TMyType;

  ptr := PMyType(bar);

or

  ptr := pointer(bar);

answered Oct 18, 2011 at 16:39

TridenT

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