ODR violation

.gitignore

*.o
*.so
main

header.hpp

#ifndef HEADER_HPP_
#define HEADER_HPP_

#include <cstdio>

template<int n>
struct widget {
    static int bar;

    static void print(const char *msg)
    {
        printf("%s %d\n", msg, bar);
    }
};

template<int n>
int widget<n>::bar;

#endif // HEADER_HPP_

libobj.cpp

#include "libobj.hpp"

void init_libmy()
{
    libmy_widget::bar = 123;
    libmy_widget::print("from init_libmy");
}

libobj.hpp

#ifndef LIBOBJ_HPP_
#define LIBOBJ_HPP_

#include "header.hpp"

typedef widget<123> libmy_widget;

void init_libmy();

#endif // LIBOBJ_HPP_

main.cpp

#include "header.hpp"
#include "libobj.hpp"

int main()
{
    widget<123>::bar = 456;
    widget<123>::print("from main"); // should be 456
    init_libmy(); // should be 123
    widget<123>::print("from main"); // is this guaranteed to output 123?
}

tryme.sh

#!/bin/sh
set -x -e

rm -rf libobj.o main.o libobj.so main

g++ -fPIC -c -o libobj.o libobj.cpp
g++ -o libmy.so libobj.o -shared -fPIC
g++ -o main.o -c main.cpp
g++ -o main main.o -lmy -L . -Wl,-rpath .

./main