1. Addr
function Addr(X): Pointer;:返回指定對象的地址。
var
I : Integer;
NodeNumbers: array [0 .. 100] of Integer;
begin
with TreeView1 do
begin
for I := 0 to Items.Count - 1 do
begin
NodeNumbers[I] := CalculateValue(Items[I]);
Items[I].Data := Addr(NodeNumber[I]);
end;
end;
end;
2. Assigned
function Assigned(const P): Boolean;:用於測試指定的對象是否爲空。其中,如果參數P存在並且不爲Nil,則返回True。
var P: Pointer;
begin
P := nil;
if Assigned (P) then Writeln ('You won''t see this');
GetMem(P, 1024); {P valid}
FreeMem(P, 1024); {P no longer valid and still not nil}
if Assigned (P) then Writeln ('You''ll see this');
end;
3. FreeAndNil
procedure FreeAndNil(var Obj);:釋放指定對象,並設置爲空。
4. Ptr
function Ptr(Address: Integer): Pointer;:將一個地址轉換爲指針。