WiringPi/examples/buttons3.c

/*
 * buttons3.c:
 *	Multiple button handling using wiringPiISRmulti.
 *
 ***********************************************************************
 * This file is part of wiringPi:
 *      https://github.com/nuncio-bitis/WiringPi
 *
 *    wiringPi is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU Lesser General Public License as published
 *by the Free Software Foundation, either version 3 of the License, or (at your
 *option) any later version.
 *
 *    wiringPi 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 Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public License
 *    along with wiringPi.  If not, see <http://www.gnu.org/licenses/>.
 ***********************************************************************
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <errno.h>
#include <wiringPi.h>

//**********************************************************************************************************************

// GPIOs (BCM) that buttons are attached to:
static const int buttons[] = { 26, 16, 20, 21 };
static const int nButtons = (sizeof (buttons) / sizeof (int));

static int terminate_process = 0;

//**********************************************************************************************************************

/**
 * Intercepts and handles signals from QNX
 * This function is called when the SIGTERM signal is raised by QNX
 */
static void Signal_handler(int sig)
{
  printf("Received signal %d\n", sig);

  // Signal process to exit.
  terminate_process = 1;
}

//**********************************************************************************************************************

static int getButtonIndex (int pin)
{
    for (int i = 0; i < nButtons; ++i)
    {
        if (buttons[i] == pin)
        {
            return i;
        }
    }
    return -1;
}

//**********************************************************************************************************************

static int nInts = 0;

static void Button_Wait (int pin)
{
  nInts++;
  printf ("%s: Interrupt on pin %d; Button #%d; nInts=%d\n", __FUNCTION__, pin, 1+getButtonIndex(pin), nInts);
}

//**********************************************************************************************************************

int main (int argc, char *argv[])
{
    // Set the handler for SIGTERM (15)
    signal(SIGTERM, Signal_handler);
    signal(SIGHUP,  Signal_handler);
    signal(SIGINT,  Signal_handler);
    signal(SIGQUIT, Signal_handler);
    signal(SIGTRAP, Signal_handler);
    signal(SIGABRT, Signal_handler);
    signal(SIGALRM, Signal_handler);
    signal(SIGUSR1, Signal_handler);
    signal(SIGUSR2, Signal_handler);

    printf ("Raspberry Pi Button Test\n");

    // ----------------------------------------------------

    wiringPiSetupGpio ();

    // Setup the inputs
    for (int i = 0; i < nButtons; ++i)
    {
        pinMode (buttons[i], INPUT);
        pullUpDnControl (buttons[i], PUD_UP);
    }

    // ----------------------------------------------------

    // Set up a callback for when any of these buttons is pressed/released
    // Note: there is no debounce proterction here.
    // You may see multiple interrupts with one button.
    if (wiringPiISRmulti ((int *)buttons, nButtons, INT_EDGE_RISING, &Button_Wait) < 0)
    {
        fprintf (stderr, "%s: Unable to setup ISR: %s\n", argv[0], strerror(errno));
        return EXIT_FAILURE;
    }

    nInts = 0;
    while (!terminate_process)
    {
        delayMs(100);
    }

    return EXIT_SUCCESS;
}

//**********************************************************************************************************************