locate /dev/input/event no. with popen()

findEventNo.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>

char event_path[30];

char *get_event_path(void){
        FILE *event_num;
        char data[10];
        const char path[] = "/dev/input/event";

        /* setup a pipe for reading and execute the command */
        event_num = popen("/bin/grep 'sysrq kbd event' /proc/bus/input/devices | /usr/bin/awk -F 'event' '{print $2}'","r");            
        if(!event_num){
                fprintf(stderr, "Could not open pipe for output\n");
                exit(1);
        }

        /* grab data from grep/awk execution */
        fgets(data, sizeof(data), event_num);
        /* merge path and data in single variable */
        snprintf(event_path, sizeof(event_path), "%s%s", path, data);

        if (pclose(event_num) != 0){
                fprintf(stderr," Error: Failed to close command stream\n");
                exit(1);
        }
        return event_path;
}



int main(void) {
        int input_device;

        get_event_path();

        input_device = open(event_path, O_RDONLY);
        if (-1 == input_device) {
                fprintf(stderr, "ERROR: Could not open %s\n", event_path);
                exit(1);
        }
        return 0;
}