use Win32::API;

Win32::API->Import('wtsapi32.dll','WTSEnumerateSessions','NNNPP','N');
Win32::API->Import('wtsapi32.dll','WTSFreeMemory','P','');

while ( 1 ) {
  my $Count = pack 'L', 0;
  my $pSessionInfo = pack 'L', 0;
  WTSEnumerateSessions(0,0,1,$pSessionInfo,$Count);
  WTSFreeMemory($pSessionInfo);
  select undef, undef, undef, 0.01;
}