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CompareDWord

Declaration:
function CompareDWord(var buf1,buf2;len:longint):longint;
Description:
CompareDWord compares two memory regions buf1,buf2 on a DWord-per-DWord basis for a total of len DWords. (A DWord is 4 bytes).

The function returns one of the following values:

-1
if buf1 and buf2 contain different DWords in the first len DWords, and the first such DWord is smaller in buf1 than the DWord at the same position in buf2.
0
if the first len DWords in buf1 and buf2 are equal.
1
if buf1 and buf2 contain different DWords in the first len DWords, and the first such DWord is larger in buf1 than the DWord at the same position in buf2.
Errors:
None.
See also:
CompareChar (468),CompareByte (466),CompareWord (472),

Listing: refex/ex101.pp

Program Example101;

{ Program to demonstrate the CompareDWord function. }

Const
  ArraySize     = 100;
  HalfArraySize = ArraySize Div 2;

Var
  Buf1,Buf2 : Array[1..ArraySize] of Dword;
  I : longint;

  Procedure CheckPos(Len : Longint);

  Begin
    Write('First ',Len,' DWords are ');
    if CompareDWord(Buf1,Buf2,Len)<>0 then
      Write('NOT ');
    Writeln('equal');
  end;


begin
  For I:=1 to ArraySize do
    begin
    Buf1[i]:=I;
    If I<=HalfArraySize Then
      Buf2[I]:=I
    else
      Buf2[i]:=HalfArraySize-I;
    end;
  CheckPos(HalfArraySize div 2);
  CheckPos(HalfArraySize);
  CheckPos(HalfArraySize+1);
  CheckPos(HalfArraySize + HalfArraySize Div 2);
end.

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