Neither of these runs the cleanup function

cleanup.c

#include <stdio.h>

static void cleanup_func(int *foo)
{
    printf("cleanup! %d\n", *foo);
}

int main(int argc, char **argv)
{
    return 0;

    int foo __attribute__((cleanup(cleanup_func))) = 1;
    return foo;
}

cleanup.cpp

#include <stdio.h>

class cleanup
{
public:
    ~cleanup();
};

cleanup::~cleanup()
{
    printf("cleanup!");
}

int main(int argc, char **argv)
{
    return 0;

    cleanup c;
    return 1;
}