What happens is the following: First signal received, namely SIGUSR1, handler is called and is running Second signal received, since handler from nr1 is still running, the signal nr2 gets pending and blocked. Third signal received, since handler from nr1 is still running, the signal 3 gets discarded. Fourth, fifth…etc signal of the same type … Read more
If you send a signal to a process, which thread in the process will handle this signal is undetermined. According to pthread(7): POSIX.1 also requires that threads share a range of other attributes (i.e., these attributes are process-wide rather than per-thread): … – signal dispositions … POSIX.1 distinguishes the notions of signals that are directed … Read more
Can’t be done. The current user is only available via the request, which is not available when using purely model functionality. Access the user in the view somehow.
You can’t have data of your own passed to the signal handler as parameters. Instead you’ll have to store your parameters in global variables. (And be really, really careful if you ever need to change those data after installing the the signal handler). Response to edit 0: Historical reasons. Signals are a really old and … Read more
You can use the os/signal package to handle incoming signals. Ctrl+C is SIGINT, so you can use this to trap os.Interrupt. c := make(chan os.Signal, 1) signal.Notify(c, os.Interrupt) go func(){ for sig := range c { // sig is a ^C, handle it } }() The manner in which you cause your program to terminate … Read more
Usually the enclosing widget encapsulates the widgets inside it and provides a higher-level interface. E.g., if W3 contains several widgets that need to be enabled/disabled depending on some state, W3 would manage that state, provide API for it and enable/disable widgets accordingly. So usually there is no need to go directly from W1 to W3. … Read more
Signals are totally different than C++ exceptions. You can’t use a C++ try/catch block to handle a signal. Specifically, signals are a POSIX concept, not a C++ language concept. Signals are delivered asynchronously to your application by the kernel, whereas C++ exceptions are synchronous events defined by the C++ standard. You are quite limited in … Read more
Simple assignment to simple variables is “atomic” AKA threadsafe (compound assignments such as += or assignments to items or attributes of objects need not be, but your example is a simple assignment to a simple, albeit global, variable, thus safe).
You can use os.kill(): os.kill(os.getpid(), signal.SIGUSR1) Put this anywhere in your code that you want to send the signal from.
You could do something like this: import subprocess as sub import threading class RunCmd(threading.Thread): def __init__(self, cmd, timeout): threading.Thread.__init__(self) self.cmd = cmd self.timeout = timeout def run(self): self.p = sub.Popen(self.cmd) self.p.wait() def Run(self): self.start() self.join(self.timeout) if self.is_alive(): self.p.terminate() #use self.p.kill() if process needs a kill -9 self.join() RunCmd([“./someProg”, “arg1”], 60).Run() The idea is that you … Read more