Problem with compile files to dynamic library

Question

I am trying compile to dynamic libary, main.c:

`#include <stdio.h>
#include <stdlib.h>
#include <math_utils.h>
int main(){
    int x,y;
    scanf("%i%i", &x, &y);
    printf("%i\n%i", gcd(x, y), lcm(x, y));
}`

math_utils.h

#pragma once

int gcd(int x, int y);

int lcm(int x, int y);

math_utils.c

#include "math_utils.h"

int gcd(int x, int y){
    int i;
    for(i = smaller(x,y); i>0; --i){
        if(x%i==0 && y%i==0){
            return i;
        }
    }
    return 0;
}

int lcm(int x, int y){
    int big = bigger(x, y);
    int small = smaller(x, y);
    int iteration = 1;
    while((big*iteration)%small!=0){
        ++iteration;
    }
    return big*iteration;
}

int smaller(int x, int y){
    if(x<y){
        return x;
    }
    return y;
}

int bigger(int x, int y){
    if(x>y){
        return x;
    }
    return y;
}

commands in the console:

1. gcc -fPIC -c math_utils.c
2. gcc -shared -o libmath.dll math_utils.o
3. gcc -o app main.c libmath.dll

After last i got it error: main.c:3:10: fatal error: math_utils.h: No such file or directory #include <math_utils.h>

Can anyone explain me ,why my main dont see math.. Thanks for every answer.

All files are in one folder

I am expecting to have dynamic library