Printing elements in a queue in a different function does not empty the queue globally in _start program. Any more explanation?

Probably this is rather a simple question but I cannot wrap around why the result is what it is. Consider the following simple code.

#include <iostream>
#include <queue>

void print_queue(std::queue<int> q)
{
    while( !queue.empty() )
    {
       std::cout << q.front()
       q.pop();
    }
    std::cout << std::endl;
    std::cout << "The size of the queue in the print function: " << q.size() << std::endl;
}


int main() {

   std::queue<int> my_queue;
   for ( const int &item : {1, 2, 3, 4, 5, 6, 7} )
   {
       q.push(item);
   }
   print(my_queue);
   std::cout << "The size of the queue in the main loop: " << my_queue.size() << std::endl;

   return 0;
}

The expected output of this will be:

1 2 3 4 5 6 7
The size of the queue in the print function: 0
The size of the queue in the main loop: 7

My question is why there is no side effect on the queue I am trying to print out. Wasn't the queue supposed to be empty at both times when the size was printed out?