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CompareWord function

In unit System

Compare 2 memory buffers word per word.

Declaration

pascal
function CompareWord(const buf1; const buf2; len: SizeInt): SizeInt

Description

CompareWord compares two memory regions buf1, buf2 on a Word-per-Word basis for a total of len Words. (A Word is 2 bytes).

The function returns one of the following values:

< 0
if buf1 and buf2 contain different Words in the first len Words, and the first such Word is smaller in buf1 than the Word at the same position in buf2.
0
if the first len Words in buf1 and buf2 are equal.
> 0
if buf1 and buf2 contain different Words in the first len Words, and the first such Word is larger in buf1 than the Word at the same position in buf2.

Errors

None.

See also

Example: ex102

pascal
Program Example102;

{ Program to demonstrate the CompareWord function. }

Const
  ArraySize     = 100;
  HalfArraySize = ArraySize Div 2;

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

  Procedure CheckPos(Len : Longint);

  Begin
    Write('First ',Len,' words are ');
    if CompareWord(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.

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.