include: co/defer.h.

#defer

defer is a macro provided by coost, which is similar to defer in golang. The argument of defer can be one or more statements.

void f() {
     void* p = malloc(32);
     defer(free(p));

     defer(
         std::cout << "111" << std::endl;
         std::cout << "222" << std::endl;
     );
     std::cout << "333" << std::endl;
}

In the above example, the code in defer will be executed at the end of function f, so 333 is printed before 111 and 222.