[fpc-pascal] Turbo Pascal and Object Pascal ways of OOP

Luiz Americo Pereira Camara pascalive at bol.com.br
Tue Feb 5 13:42:42 CET 2008

Daniƫl Mantione wrote:
> Stack allocation is much faster than heap allocation, and automatic. 
> Take a look at the matrix unit; you can return an object from a 
> function without worrying about memory leaks, so they are very usefull 
> in function results and operator overloading.
> Further, objects allow you control the binary layout (the binary 
> layout is just like a record), which means you can fit existing data 
> structures (like those used in files) with methods. Some time ago we 
> had a discussion about this list about mapping the GTK Gobject model 
> to Pascal objects, succesfull experiments were done.

In a external c library, i have a structure like

TMyType = record
  x: Integer;
  y: Integer;
PMyType = ^TMyType;

and a function that expects a pointer to that record

function DoIt(MyVar: PMyType);

can i safely use the below object  instead of the record and pass 
directly to the c function?

TMyObj = object
  x: Integer;
  y: Integer;
PMyObj = ^TMyObj;

Moreover, whats the difference between objects and records with methods 
(the new Delphi feature)?


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