How to translate this:

struct a;

Mattias

er...

Closest would be:

type
     record = foo
        bar  : integer;
     end;
var
    a  : foo;

I _think_.

g.

Mattias Gärtner wrote

How to translate this: struct a;

Isn't this a forward declaration? So sometime later it needs to declare 'struct a { ... };' ?

Micha

No. The a is not an instantiation, it's an incomplete type. I wouldn't translate it at all, it's merely a forward declaration. As the (C-)compiler wouldn't know the size of the type at this point, it can't instantiate anything (although pointer to it would be possible, AFAIR).

Vinzent.

Gene Buckle wrote

> How to translate this: > > struct a;

a: pointer;

I would do something like this:

C
----------------------------
struct product {
  int weight;
  float price;
} ;
product apple;
-----------------------------
Pascal
----------------------------
Type
   product = record
      weight: Integer ;
      price: double;
    end;
Var
  apple: product ;
----------------------------

This is the reason that I do believe that is missing something on the code:

struct a;

Best Regards

Lourival Mendes

2008/7/30 Jilani Khaldi :

A C-struct is merely a record. A struct with methods is a class.

struct Foo
{
Foo() : tag(0) {}

     int tag;
     void compute() {...}

};

would be

class Foo
private
   FTag: Integer;
public
   constructor Create;
   procedure compute;
   property tag: Integer read FTag write FTag;
end;

the property is not really needed of course.

If not, can't it be translated as:

   a: record end;

?

Marc (not a Cist)

Yes, it can.

Thanks. I will use that.

Mattias

Vinzent Höfler wrote

What for? The C statement is empty, it's not a variable and not even a type. So before translating that into an empty Pascal-record, you should rather look at what the actually used structur in the C-code is.

It is usually used for having an opaque type, referencing it with a pointer. I would put in pascal both the empty structure and a pointer type to it.

  a: record end;
  pa: ^a;

What for? The C statement is empty, it's not a variable and not even a type. So before translating that into an empty Pascal-record, you should rather look at what the actually used structur in the C-code is.

Vinzent.

But then the structures won't match, opaque or not.

Mattias provided no context to his original question, so I don't know if it would impose a problem, but usually I leave those things out until I really need them. The type as is has no storage size associated to it, so it can't even be used that way in the C-code. Sure, you can have a pointer to it, but unless you cast the hell out of it, it still won't do any good.

Vinzent.

Zitat von Vinzent Höfler :

Actually the C-Code does what C can do really good: obfuscating.

If I understand the code correct, the 'struct a;' itself is never used directly. It always uses 'struct a* foo'. So foo is a pointer to an empty struct a, which probably is the C equivalent of a typed pointer. To get strong type checking, I guess, it is ok to follow Felipe's advice:

type a = record end; pa=^a;

Mattias

Yeah.

Well, I guess so, but it still doesn't make a lot of sense.

That "struct a" is not empty (storage size = 0), it is even non-existant (storage size = unknown). So the C-code may shuffle around the pointers, but unless this "struct a" (the "a" not even being a type here) is instantiated somewhere (internally in some library code?) such pointers are merely typed "void*".

Vinzent.

Zitat von Vinzent Höfler :

The c compiler does not need the internals, so should the pascal bindings.

Mattias