MoveMemory、CopyMemory 的功能类似, 都是复制内存, 都是调用 Move 过程;

MoveMemory、CopyMemory 操作指针; Move 操作实体.

还要注意, 它们的参数位置不一样!

{例1}
var
  buf1,buf2: array[0..9] of AnsiChar;
begin
  buf1 := '0123456789';
  buf2 := 'abcdefghij';

  Move(buf2[2], buf1[4], 5);

  ShowMessage(buf1); {0123cdefg9}
  ShowMessage(buf2); {abcdefghij}
end;

{例2}
var
  buf1,buf2: array[0..9] of AnsiChar;
begin
  buf1 := '0123456789';
  buf2 := 'abcdefghij';

  CopyMemory(@buf2[2], @buf1[4], 5);

  ShowMessage(buf1); {0123456789}
  ShowMessage(buf2); {ab45678hij}
end;

{例3}
var
  s1,s2: TStringStream; {两个字符串流}
begin
  s1 := TStringStream.Create;
  s2 := TStringStream.Create;

  {向第一个字符串流写入}
  s1.WriteString('万一的 Delphi 博客');
  ShowMessage(s1.DataString); {万一的 Delphi 博客}

  {设置第二个字符串流的大小}
  s2.SetSize(6);
  {从第一个流复制到第二个流}
  CopyMemory(s2.Memory, s1.Memory, s2.Size);
  ShowMessage(s2.DataString); {万一的}

  s1.Free;
  s2.Free;
end;