BLSignal.hh

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//      BLSignal.cc
/*
This source file is part of G4beamline, http://g4beamline.muonsinc.com
Copyright (C) 2003,2004,2005,2006 by Tom Roberts, all rights reserved.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

http://www.gnu.org/copyleft/gpl.html
*/

#ifndef BLSIGNAL_HH
#define BLSIGNAL_HH

/**     class BLSignal implements a signal handler to permit G4beamline
 *      to exit cleanly when a UNIX signal is received.
 *
 *      SIGUSR1 and SIGUSR2 are special, and do not exit the program;
 *      they are merely reported via functions sigusr1() and sigusr2().
 *
 *      Note that a second received signal causes an immediate call to
 *      g4bl_exit() from the signal handler.
 *
 *      If BLAlarm is also used, BLSignal::init() must be called first.
 *
 *      Note that BLManager checks received() in UserSteppingAction(), and
 *      issues a fatal exception when any signal is received..
 **/
class BLSignal {
public:
        /// init() will setup the signal handler
        static void init();

        /// received() returns true if a signal has been received.
        /// Does not include SIGUSR1 or SIGUSR2. Does not include SIGALRM
        /// if BLAlarm is used.
        static bool received() { return signalReceived; };

        /// value() returns the signal # of the last sginal received.
        /// Does not include SIGUSR1 or SIGUSR2. Does not include SIGALRM
        /// if BLAlarm is used.
        static int value() { return prev; }

        /// clear() will clear the signalReceived flag.
        void clear() { signalReceived = false; prev = 0; }

        /// setSignalReceived() will set the signalReceived flag.
        static void setSignalReceived(bool v) { signalReceived = v; }

        /// sigusr1() returns true if one or more SIGUSR1 signals was
        /// received since the last call;
        static bool sigusr1() { bool v=usr1; usr1=false; return v; }

        /// sigusr2() returns true if one or more SIGUSR2 signals was
        /// received since the last call;
        static bool sigusr2() { bool v=usr2; usr2=false; return v; }

private:
        static bool signalReceived;
        static bool usr1, usr2;
        static int prev;

        /// sighandler() handles the alarm signal
        static void sighandler(int sig);
};

#endif // BLSIGNAL_HH