Dynamic library cause crash at runtime (Windows)

I'm currently trying to create a dynamic library (just a test to see how it works) and so far I've been able to create a .dll file and link it to another .c file but when I'm running my program nothing is shown on the terminal (even if there is a printf() before a call to the library function)

Here are the files for the dll :

test.h
-----------------
#pragma once
void foo();

test.c
-----------------
#include <stdio.h>
#include "test.h"

void foo() {
    printf("LOLOLOLO\n");
}

That I've compiled with :

gcc test.c -c -o test.o
gcc test.o -fPIC -shared -o libtest.dll

My main .c file which import my dll (that I won't rewrite it here because it does nothing except call foo in main with just a printf before and after foo to check that everything is doing fine) compile with no errors nor warnings because I added the -L... and -I... necessary (and -ltest).
So I don't understand why it does not run.

Thanks in advance for the answers !

Edit : I just want to precise that if I export my library statically, it works perfectly

Edit2 : Here is the main program using foo

#include <stdio.h>
#include "test.h"

int main() {
    printf("start\n");
    foo();

    printf("end\n");
    return 0;
}

I've found the solution.

I didn't know that it was NECESSARY on windows (because all the tutorials are on linux) to use the command __declspec(dllexport) for the library to works.

I hope it'll help someone in the future !