Sum of all the multiples of 3 or 5 below 1000 gives a wrong answer in C

Question

Project Euler problem:

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9

Answer 1

For the fun of it, I decided on giving the problem some additional constraints.

• The loop iterator can not take values that aren't a multiple
• The numbers must be added to the sum in numerical order.

---

int sum_multiples(long int m1,long int m2,long int lim)
{
    long int sum=0;
    for(long int i=m1;i((i+m2)/m2)*m2?((i+m2)/m2)*m2:((i+m1)/m1)*m1) sum+=i;
    return sum;
}
int  main(int argc, char *argv[])
{
    printf("Total: %ld \n",sum_multiples(3,5,1000));
    return 0;
}