Simple tremor emulator

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/input.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>

int cleanSTDIN()
{
        while (getchar()!='\n');
        return 1;
}

long getInteger(char* msg, long from, long till)
{
        int count = 0;
        long m    = 0;
        char c;
        do
        {
                printf("\n");
                printf(msg);

        } while (((scanf("%d%c", &m, &c)!=2 || c!='\n') && cleanSTDIN()) || m<from || m>till);

        return m;
}
long randomTill(long max)
{
        unsigned long
        numBin  = (unsigned long) max + 1,
        numRand = (unsigned long) RAND_MAX + 1,
        binSize = numRand / numBin,
        defect  = numRand % binSize;

        long z;
        while (numRand - defect <= (unsigned long)(z = random()));
        return z/binSize;
}

int main()
{
        struct input_event event, event_end;

        int  fd = open("/dev/input/event4", O_RDWR);
        long ma = getInteger("Enter max amplitude [points, 0..50]: ", 0, 50);
        long ta = getInteger("Enter max wait time [usecs , 0..200000]: ", 0, 200000);
        if (fd < 0)
        {
                printf("Mouse access attempt failed:%s\n", strerror(errno));
                return -1;
        }
        memset(&event, 0, sizeof(event));
        memset(&event, 0, sizeof(event_end));
        gettimeofday(&event.time, NULL);
        event.type = EV_REL;
        gettimeofday(&event_end.time, NULL);
        event_end.type = EV_SYN;
        event_end.code = SYN_REPORT;
        event_end.value = 0;
        while(1)
        {
                event.code  = rand() % 2 ? REL_X : REL_Y;
                event.value = (rand() % 2 ? -1 : 1)*randomTill(ma);
                write(fd, &event, sizeof(event));
                write(fd, &event_end, sizeof(event_end));
                usleep(randomTill(ta));
        }
        close(fd);
        return 0;
}