Cardinal

│ Deutsch (de) │ English (en) │ français (fr) │ русский (ru) │

Cardinal is an integer type defined as an alias for DWord under a 32-bit platform. Like the DWord (double word) type it's 32 bits and interpreted as an unsigned integer. As it's only used on 32-bit systems, its minimal value is 0x0000000 and its maximal value 0xFFFFFFFF (4,294,967,295).

On x86 systems Cardinal type is often used to hold a memory address, like a pointer:

 var
   AnAddress: Cardinal;
   AnObject: TObject;
 begin
   AnAddress := Cardinal(Self);
   with TObject(AnAddress) do
   begin
     // AnAddress is casted as a TObject.
   end;
 end;
 

However, because of 32 and 64 bit little endian systems, using the Cardinal type is not recommended anymore for memory/pointer operations/arithmetic. It's recommended to use NativeInt or NativeUInt types instead. These types will match the width of the CPU registers which can be used to encode a memory address and so will always be the right size. For example under a 64b-bit OS, a NativeUInt will be like a UInt64 or a QuadWord and under a 32-bit OS, a NativeUInt will be like a DWord or a Cardinal.