Function try_get_shared_from_this

include/pybind11/detail/common.h:1354–1369

template <typename T>
inline static std::shared_ptr<T>
try_get_shared_from_this(std::enable_shared_from_this<T> *holder_value_ptr) {
// Pre C++17, this code path exploits undefined behavior, but is known to work on many platforms.
// Use at your own risk!
// See also https://en.cppreference.com/w/cpp/memory/enable_shared_from_this, and in particular
// the `std::shared_ptr<Good> gp1 = not_so_good.getptr();` and `try`-`catch` parts of the example.
#if defined(__cpp_lib_enable_shared_from_this) && (!defined(_MSC_VER) || _MSC_VER >= 1912)
    return holder_value_ptr->weak_from_this().lock();
#else
    try {
        return holder_value_ptr->shared_from_this();
    } catch (const std::bad_weak_ptr &) {
        return nullptr;
    }
#endif
}

// For silencing "unused" compiler warnings in special situations.
template <typename... Args>