How to create a wrapper for `std::make_unique<T>`?
I'd like to create a wrapper for std::unique_ptr<T>
and std::make_unique<T>
because I think they look ugly and take too long to type. (Yes, I'm that kind of person).
I have completed my UniquePtr
type alias with no problem but cannot get my MakeUnique
to work. It seems to be a bit of a rabbit hole, and was wondering if anyone here might be able to give me a hand with this?
What I have so far:
template <class T>
using UniquePtr = std::unique_ptr<T>;
template<typename T, typename... Args>
UniquePtr<T> MakeUnique<T>(Args... args) // recursive variadic function
{
return std::make_unique<T>(args);
}
Many thanks in advance!
Solution 1:
You need to forward properly the values, and you need to expand the pack.
First, make it compile:
template<typename T, typename... Args>
UniquePtr<T> MakeUnique(Args... args) // not recursive
{ // ^---- no need for <T> when defining function template
return std::make_unique<T>(args...); // the ... expands the pack
}
Then, you need to forward, because args...
will copy everything. You want to move rvalues, and copy lvalues:
template<typename T, typename... Args>
UniquePtr<T> MakeUnique(Args&&... args)
{
return std::make_unique<T>(std::forward<Args>(args)...);
}