View Compilation Error

0_0_22497450_26210.cpp: In function 'int min_div(int, int)':
0_0_22497450_26210.cpp:28:2: error: 'thread' was not declared in this scope
  thread thrd_front(min_div,beg,ins_dest);
  ^
0_0_22497450_26210.cpp:29:9: error: expected ';' before 'thrd_back'
  thread thrd_back(min_div,ins_dest+1,end);
         ^
0_0_22497450_26210.cpp:30:2: error: 'thrd_front' was not declared in this scope
  thrd_front.join();
  ^
0_0_22497450_26210.cpp:31:2: error: 'thrd_back' was not declared in this scope
  thrd_back.join();
  ^