How do I use std::unique_ptr in C++ templates?

How do I use std::unique_ptr in C++ templates?

You can use std::unique_ptr in templates by defining a template class or function that takes a unique_ptr as a parameter. Here's a simple example.

Can you show me a code example?

Sure! Here's a template function that takes a std::unique_ptr:

#include <iostream>
#include <memory>

template <typename T>
void processUniquePtr(std::unique_ptr<T> ptr) {
    if (ptr) {
        std::cout << "Processing: " << *ptr << std::endl;
    }
}

int main() {
    std::unique_ptr<int> myPtr = std::make_unique<int>(42);
    processUniquePtr(std::move(myPtr));
    return 0;
}

What happens if I try to pass a unique_ptr by value?

If you pass a std::unique_ptr by value, it will be moved into the function, leaving the original pointer null. This is because unique_ptr is non-copyable.

Is there a way to pass it by reference instead?

Yes, you can pass it by reference using std::unique_ptr<T>& in your template function. This way, the original unique_ptr remains valid after the function call.