# _signal - pydoc - phpman Help on built-in module _signal: ## NAME _signal - This module provides mechanisms to use signal handlers in Python. ## DESCRIPTION Functions: ### alarm ### setitimer float time and the timer may restart then [Unix only] ### getitimer ### signal ### getsignal ### pause ### default_int_handler signal constants: SIG_DFL -- used to refer to the system default handler SIG_IGN -- used to ignore the signal NSIG -- number of defined signals SIGINT, SIGTERM, etc. -- signal numbers itimer constants: 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 ITIMER_PROF -- decrements both when the process is executing and when the system is executing on behalf of the process. Coupled with ITIMER_VIRTUAL, this timer is usually used to profile the time spent by the application in user and kernel space. SIGPROF is delivered upon expiration. *** IMPORTANT NOTICE *** A signal handler function is called with two arguments: the first is the signal number, the second is the interrupted stack frame. ## FUNCTIONS ### alarm Arrange for SIGALRM to arrive after the given number of seconds. ### default_int_handler The default handler for SIGINT installed by Python. It raises KeyboardInterrupt. ### getitimer Returns current value of given itimer. ### getsignal Return the current action for the given signal. The return value can be: SIG_IGN -- if the signal is being ignored SIG_DFL -- if the default action for the signal is in effect None -- if an unknown handler is in effect anything else -- the callable Python object used as a handler ### pause Wait until a signal arrives. ### pidfd_send_signal Send a signal to a process referred to by a pid file descriptor. ### pthread_kill Send a signal to a thread. ### pthread_sigmask Fetch and/or change the signal mask of the calling thread. ### raise_signal Send a signal to the executing process. ### set_wakeup_fd set_wakeup_fd(fd, *, warn_on_full_buffer=True) -> fd Sets the fd to be written to (with the signal number) when a signal comes in. A library can use this to wakeup select or poll. The previous fd or -1 is returned. The fd must be non-blocking. ### setitimer Sets given itimer (one of ITIMER_REAL, ITIMER_VIRTUAL or ITIMER_PROF). The timer will fire after value seconds and after that every interval seconds. The itimer can be cleared by setting seconds to zero. Returns old values as a tuple: (delay, interval). ### siginterrupt Change system call restart behaviour. If flag is False, system calls will be restarted when interrupted by signal sig, else system calls will be interrupted. ### signal Set the action for the given signal. The action can be SIG_DFL, SIG_IGN, or a callable Python object. The previous action is returned. See getsignal() for possible return values. *** IMPORTANT NOTICE *** A signal handler function is called with two arguments: the first is the signal number, the second is the interrupted stack frame. ### sigpending Examine pending signals. Returns a set of signal numbers that are pending for delivery to the calling thread. ### sigtimedwait Like sigwaitinfo(), but with a timeout. The timeout is specified in seconds, with floating point numbers allowed. ### sigwait Wait for a signal. Suspend execution of the calling thread until the delivery of one of the signals specified in the signal set sigset. The function accepts the signal and returns the signal number. ### sigwaitinfo Wait synchronously until one of the signals in *sigset* is delivered. Returns a struct_siginfo containing information about the signal. ### strsignal Return the system description of the given signal. The return values can be such as "Interrupt", "Segmentation fault", etc. Returns None if the signal is not recognized. ### valid_signals Return a set of valid signal numbers on this platform. The signal numbers returned by this function can be safely passed to functions like `pthread_sigmask`. ## DATA ITIMER_PROF = 2 ITIMER_REAL = 0 ITIMER_VIRTUAL = 1 NSIG = 65 SIGABRT = 6 SIGALRM = 14 SIGBUS = 7 SIGCHLD = 17 SIGCLD = 17 SIGCONT = 18 SIGFPE = 8 SIGHUP = 1 SIGILL = 4 SIGINT = 2 SIGIO = 29 SIGIOT = 6 SIGKILL = 9 SIGPIPE = 13 SIGPOLL = 29 SIGPROF = 27 SIGPWR = 30 SIGQUIT = 3 SIGRTMAX = 64 SIGRTMIN = 34 SIGSEGV = 11 SIGSTOP = 19 SIGSYS = 31 SIGTERM = 15 SIGTRAP = 5 SIGTSTP = 20 SIGTTIN = 21 SIGTTOU = 22 SIGURG = 23 SIGUSR1 = 10 SIGUSR2 = 12 SIGVTALRM = 26 SIGWINCH = 28 SIGXCPU = 24 SIGXFSZ = 25 SIG_BLOCK = 0 SIG_DFL = 0 SIG_IGN = 1 SIG_SETMASK = 2 SIG_UNBLOCK = 1 ## FILE (built-in)