Can I allocate unique_ptr outside the function?

Is this correct? So can I allocate the dynamic var outside the function?

TMyClass* ClassA::myAllocFunc()
{
 return new MyClass;
}

void ClassA::myFunc()
{
 std::unique_ptr<MyClass> l(myAllocFunc);
 
}

Yes, you can have a function return a raw pointer and have std::unique_ptr take ownership of it.

In your example, you just need to call the function and pass its return value to std::unique_ptr, not try to pass the function itself, eg:

std::unique_ptr<MyClass> l(myAllocFunc()); // <-- notice the extra '()'

That being said, a better option would be to have myAllocFunc() return a std::unique_ptr to begin with, not return a raw pointer, eg:

std::unique_ptr<TMyClass> ClassA::myAllocFunc()
{
    return std::make_unique<MyClass>();
}

void ClassA::myFunc()
{
    std::unique_ptr<MyClass> l = myAllocFunc();
    // or simply:
    // auto l = myAllocFunc();
}