Behavior of std::bind and std::function

std::bind

Because of std::bind, you can create function objects in a variety of ways:

• bind the arguments to an arbitrary position,
• change the order of the arguments,
• introduce placeholders for arguments,
• partially evaluate functions,
• invoke the newly created function objects, use them in the algorithm of the STL or store them in std::function.

std::function

std::function can store arbitrary callables in variables. It’s a kind of polymorphic function wrapper. A callable may be a lambda function, a function object, or a function. std::function is always necessary and can’t be replaced by auto, if you have to specify the type of the callable explicitly.