4/4 with arbitrary BPM "metronome" in C

beat.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define MINUTE_MS 60000

void tick(useconds_t);

int main(int argc, char *argv[]){
	
	if(argc != 2) {
		fprintf(stderr, "usage: %s bpm\n", argv[0]);
		return EXIT_FAILURE;
	}
	
	long int tempo = atoi(argv[1]);
	
	if(tempo > 320) {
		fprintf(stderr, "U mad bro?\n");
		return EXIT_FAILURE;
	}
	
	useconds_t sleepValue = ((MINUTE_MS / tempo) * 1000);
	tick(sleepValue);
	return 0;
}

void tick(useconds_t tock) {
	int fract = 1;
	while(1) {
		printf("Tick! %d/4\n", fract);
		usleep(tock);
		if(fract == 4) {
			fract = 0;
			printf("\n");
		}
		fract++;
	}
}