820             std::thread t2(f1, n + 1);  variable
821             t2.detach(); // test detach
824         std::thread t2(f1, n + 1); // pass by value  variable
830         EXPECT_EQ(t2.joinable(), true);
831         t2.join();
832         EXPECT_EQ(t2.joinable(), false);
846             ffrt::thread t2(f1, n + 1);  variable
847             t2.detach(); // test detach
850         ffrt::thread t2(f1, n + 1); // pass by value  variable
856         EXPECT_EQ(t2.joinable(), true);
857         t2.join();
858         EXPECT_EQ(t2.joinable(), false);