Книга: Standard Template Library Programmer

ptr_fun

ptr_fun

Categories: functors, adaptors

Component type: function

template <class Arg, class Result>
pointer_to_unary_function<Arg, Result> ptr_fun(Result (*x)(Arg));
template <class Arg1, class Arg2, class Result>
pointer_to_binary_function<Arg1, Arg2, Result> ptr_fun(Result (*x)(Arg1, Arg2));

Ptr_fun takes a function pointer as its argument and returns a function pointer adaptor, a type of function object. It is actually two different functions, not one (that is, the name ptr_fun is overloaded). If its argument is of type Result (*)(Arg) then ptr_fun creates a pointer_to_unary_function, and if its argument is of type Result (*)(Arg1, Arg2) then ptr_fun creates a pointer_to_binary_function.

Defined in the standard header functional, and in the nonstandard backward-compatibility header function.h.

The argument must be a pointer to a function that takes either one or two arguments. The argument type(s) and the return type of the function are arbitrary, with the restriction that the function must return a value; it may not be a void function.

See the examples in the discussions of pointer_to_unary_function and pointer_to_binary_function.

Function Objects, pointer_to_unary_function, pointer_to_binary_function, Adaptable Unary Function, Adaptable Binary Function

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