result_type
from the base classes unary_function
and binary_function
). Sometimes those typedefs are required, not just optional.
Adaptors are provided to turn pointers to unary (single-argument) and binary (double-argument) functions into function objects. The long-winded functor pointer_to_unary_function
is constructed with a function pointer f
, and its operator()
called with argument x
returns f(x)
. The functor pointer_to_binary_function
does the same thing, but with a double-argument f
and operator()
.
The function ptr_fun
takes a pointer-to-function f
and constructs an instance of the appropriate functor.
pointer_to_binary_function<_Arg1, _Arg2, _Result> std::ptr_fun | ( | _Result(*)(_Arg1, _Arg2) | __x | ) | [inline] |
pointer_to_unary_function<_Arg, _Result> std::ptr_fun | ( | _Result(*)(_Arg) | __x | ) | [inline] |