使うことなんてないと思うけれど、一応メモ。
Windows系コンパイラなら問題なくコンパイルできると思う。
一応、MinGWでコンパイル、動作確認は行った。

#include <windows.h>
#include <stdio.h>

int main(void)
{
  unsigned int GV = GetVersion();

  printf("GetVersion API(GV)                        = %08X\n\n", GV);
  printf("_winver                                   = %08X\n", _winver);
  printf("_winmajor                                 = %08X\n", _winmajor);
  printf("_winminor                                 = %08X\n", _winminor);
  printf("_osver                                    = %08X\n\n", _osver);
  printf("(( GV << 8 ) | (( GV >> 8 ) & 0XFF)) & 0XFFFF = %08X (= _winver)\n",
                  (( GV << 8 ) | (( GV >> 8 ) & 0XFF)) & 0XFFFF );
  printf("GV & 0XFF                                 = %08X (= _winmajor)\n",
                  GV & 0XFF );
  printf("( GV >> 8 ) & 0XFF                          = %08X (= _winminor)\n",
                  (( GV >> 8 ) & 0XFF));
  printf("GV >> 16                                  = %08X (= _osver)\n\n\n",
                  (GV >> 16) );

  // Windows version(_winmajor, _winminor, _osver)
  printf("This system is [");
  if ( _osver < 0X8000 ) {
    // NT Group (_osver LowWORD MSB = 0)
    switch (_winmajor) {
      case 3:
      case 4:
        printf ("Windows NT %u.%u Build %u",
                         _winmajor, _winminor, _osver);
        break;
      case 5:
        switch (_winminor) {
          case 0:
            printf ("Windows 2000 Build %u", _osver);
            break;
          case 1:
            printf ("Windows XP Build %u", _osver);
            break;
          case 2:
            printf ("Windows Server 2003 family Build %u",
                                    _osver);
            break;
          default:
            printf ("NT Group Windows Build %u", _osver);
        }
        break;
      case 6:
        switch (_winminor) {
          case 0:
            printf ("Windows Vista or Windows Server 2008 Build %u", _osver);
            break;
          case 1:
            printf ("Windows 7 Build %u", _osver);
            break;
          default:
            printf ("NT Group Windows Build %u", _osver);
        }
        break;
      default:
        printf ("NTGroup Windows Build %u", _osver);
    }
  }
  else {
    switch (_winmajor ) {
      case 0: //Win32s Group
      case 1:
      case 2:
      case 3:
        printf ("Win32s Build %u", _osver & 0X7FFF);
        break;
      case 4: // 9X Group (_osver is invalid.)
        switch (_winminor) {
          case 0:
            printf ("Windows 95 Build ----");
            break;
          case 10:
            printf ("Windows 98 Build ----");
            break;
          case 90:
            printf ("Windows Me Build ----");
            break;
          default: // To make sure
            printf ("Newer than Windows Me");
        }
        break;
      default: // To make sure
        printf ("Newer than Windows Me");
    }
  }
  printf("]");

  return 0;
}