obs_enum_sources never callbacks

[lepidodendraceae]

#include <libobs/obs.h>
#include <stdio.h>
#include <windows.h>

bool enum_source_proc(void* _, obs_source_t* source)
{
    const char* name = obs_source_get_name(source);
    if (name != NULL)
    {
        printf("device: %s\n", name);
    }

    return true;
}

int main()
{
    obs_startup("en-US", NULL, NULL);
    obs_enum_sources(enum_source_proc, NULL);

    Sleep(5000);
    obs_shutdown();
    return 0;
}

The enum_source_proc is never called and I am assured that the camera device is present on my device, am I missing something?