WinAPI: GetUserName 获取当前用户名

//声明:
GetUserName(
  lpBuffer: PChar;  {缓冲区}
  var nSize: DWORD  {缓冲区大小}
): BOOL;


//举例:
var
  arr: array[0..254] of Char;
  d: DWORD;
begin
  d := SizeOf(arr);
  GetUserName(arr, d);
  ShowMessage(arr);   {wy}
end;


//另一例:
var
  p: PChar;
  num: DWORD;
begin
  num := 0;
  GetUserName(nil, num);
  ShowMessage(IntToStr(num));

  GetMem(p, num);

  GetUserName(p, num);
  ShowMessage(p);     {wy}

  FreeMem(p);
end;


//再一例:
var
  p: PChar;
  num: DWORD;
begin
  num := 0;
  GetUserName(nil, num);

  p := StrAlloc(num);

  if GetUserName(p,num) then
    ShowMessage(p)          {wy}
  else ShowMessage('无');

  StrDispose(p);
end;