View Compilation Error

0_0_13121349_28448.c: In function 'main':
0_0_13121349_28448.c:7:2: error: unknown type name '_int64'
  _int64 pp, a[10000];
  ^
0_0_13121349_28448.c:17:22: error: '_int64' undeclared (first use in this function)
   qsort(a, n, sizeof(_int64), cmp);
                      ^
0_0_13121349_28448.c:17:22: note: each undeclared identifier is reported only once for each function it appears in
0_0_13121349_28448.c: In function 'cmp':
0_0_13121349_28448.c:35:11: error: '_int64' undeclared (first use in this function)
  return *(_int64 *)a-*(_int64*)b;
           ^
0_0_13121349_28448.c:35:19: error: expected expression before ')' token
  return *(_int64 *)a-*(_int64*)b;
                   ^