Sig_sender sigusr1 sender: about to send signal 16. Sig_handler::interrupt() got signal 16 main: all done. Sig_task sigusr1 task, woke up for signal 16. Sig_sender sigusr1 sender: about to send signal 16. Sig_handler::interrupt() got signal 16 Sig_task sigusr1 task, woke up for signal 16. Sig_sender sigusr1 sender: about to send signal 16. Sig_handler::interrupt() got signal 16 Sig_task sigusr1 task, woke up for signal 16. Sig_sender sigusr1 sender: about to send signal 16. Sig_handler::interrupt() got signal 16 Sig_task sigusr1 task, woke up for signal 16. Sig_sender sigusr1 sender: about to send signal 16. Sig_handler::interrupt() got signal 16 Sig_task sigusr1 task, woke up for signal 16. Sig_task sigusr1 task: all done. Sig_sender sigusr1 sender: all done.