signals

I am building some rudimentary crash logging system based on this blog post ( Yes , I am aware of PLCRashReporter, and No , I can't use it and need to roll my own, however limited. Thank you). My code registers both an exception handler (with NSSetUncaughtExceptionHandler() ) and a signal handler for most signals: SIGQUIT SIGILL SIGTRAP SIGABRT SIGEMT SIGFPE SIGBUS SIGSEGV SIGSYS SIGPIPE SIGALRM SIGXCPU SIGXFSZ It seems to work fine with basic Objective-C stuff such as "unrecognized selector sent to instance...", etc. Next, I tried it with the following Swift code: var empty:String! = nil let

In unix, If a multi-threaded process was sent a signal, which thread will be the one to execute the handling function? if it is a multi-cpu machine, more than 1 thread is running at the same time. which thread will be the on to run the signal handling function? Jonathan According to man 7 signal , all threads in the process share the same signal handler, and if a signal is delivered to a process with multiple threads that have not blocked the signal, one of them is arbitrarily chosen to receive it. Having a multi-CPU machine will not change these semantics. 来源： https://stackoverflow.com

I am not being flip I really don't get it. I just read a whole bunch of material on them and I can't figure out the use case. I am not talking talking so much about the API for which the advantages over things like signal() are clear enough. Rather it seems RT signals are meant to be user space generated but to what end? The only use seems to be a primitive IPC but everything points to them being a lousy form of IPC (e.g. awkward, limited information, not particularly efficient, etc). So where and how are they used? First of all, note that Ben's answer is correct. As far as I can tell, the

My program goes through a loop like this: ... while(1){ read(sockfd,buf,sizeof(buf)); ... } The read function blocks when it is waiting for input, which happens to be from a socket. I want to handle SIGINT and basically tell it to stop the read function if it is reading and then call an arbitrary function. What is the best way to do this? From read(2) : EINTR The call was interrupted by a signal before any data was read; see signal(7). If you amend your code to look more like: cont = 1; while (1 && cont) { ret = read(sockfd, buf, sizeof(buf)); if (ret < 0 && errno == EINTR) cont = arbitrary

Is it possible to trap Linux signals (e.g. SIGUSR1) through an handler in Erlang? (without having to resort to a driver crafted in C) (NOT A REAL ANSWER) In 2001 someone asked: Does anyone have any examples of unix signal handling in erlang. I would like to make a loadbalancer that I have written respond to sighup. At that time the answer was: There is no provision for handling signals in Erlang "itself", i.e. you will need to use a driver - or a port program of course, might actually be a better idea. Also for the driver case, the emulator has its own handler for a number of signals, and

I'm really uncertain about the requirements POSIX places on the safety of fork in the presence of threads and signals. fork is listed as one of the async-signal-safe functions, but if there is a possibility that library code has registered pthread_atfork handlers which are not async-signal-safe, does this negate the safety of fork ? Does the answer depend on whether the thread in which the signal handler is running could be in the middle of using a resource that the atfork handlers need? Or said a different way, if the atfork handlers make use of synchronization resources (mutexes, etc.) but

Is there a way to see which signals have been set in Django? It's not really exposed in docs but Signal is just a class that contains a list of receivers which are called on event. You can manually check this list: from django.db.models.signals import * for signal in [pre_save, pre_init, pre_delete, post_save, post_delete, post_init, post_syncdb]: # print a List of connected listeners print signal.receivers priestc There's a django app called django-debug-toolbar which adds a little toolbar at the top of all django served pages providing info related to the backend of the page's rendering,

I've got a command that I'm wrapping in script and spawning from a Python script using subprocess.Popen . I'm trying to make sure it dies if the user issues a SIGINT . I could figure out if the process was interrupted in a least two ways: A. Die if the wrapped command has a non-zero exit status (doesn't work, because script seems to always return 0) B. Do something special with SIGINT in the parent Python script rather than simply interrupting the subprocess. I've tried the following: import sys import signal import subprocess def interrupt_handler(signum, frame): print "While there is a