[C++][recap] forward

https://en.cppreference.com/w/cpp/utility/forward


Perfect forwarding isn't really perfect. There are several kinds of arguments that cannot be perfectly forwarded, including (but not necessarily limited to):

• 0 as a null pointer constant.
• Names of function templates (e.g., std::endl and other manipulators).
• Braced initializer lists.
• In-class initialized const static data members lacking an out-of-class definition.
• Bit fields.

For details consult the comp.std.c++ discussion, “ Perfect Forwarding Failure Cases,”referenced in the Further Information section of the course.