python timer mystery
好吧，至少对我来说是一个谜。 考虑以下：
1 2 3 4 5 6 7 8 9 10 11 | import time import signal def catcher(signum, _): print"beat!" signal.signal(signal.SIGALRM, catcher) signal.setitimer(signal.ITIMER_REAL, 2, 2) while True: time.sleep(5) |
按预期工作，即提供"节拍！" 消息每2秒。 接下来，没有产生输出：
1 2 3 4 5 6 7 8 9 10 11 | import time import signal def catcher(signum, _): print"beat!" signal.signal(signal.SIGVTALRM, catcher) signal.setitimer(signal.ITIMER_VIRTUAL, 2, 2) while True: time.sleep(5) |
问题在哪里？
从我的系统的man setitimer(强调我的)：
The system provides each process with three interval timers, each decrementing in a distinct time domain. When any timer expires, a signal is sent to the process, and the timer (potentially) restarts.
ITIMER_REAL decrements in real time, and delivers SIGALRM upon expiration.
ITIMER_VIRTUAL decrements only when the process is executing, and delivers SIGVTALRM upon expiration.
您是否只是想念您的过程在睡觉时没有执行？ 你需要花费很长时间才能在这个循环中累积实际使用的时间。