Overview

Nullary functions are defined as an object (c++ class/struct) that is sometimes otherwise known as callable without any argument passing.

Compiling & Linking

Include the following at the top of any translation unit for which you are running compile time checks on your blueprint classes.

#include <ecl/concepts.hpp>
 
using ecl::NullaryFunctionConcept;

Since it only uses macros and templatised objects, no linking is required for just this feature.

Concept Definition

Creating a class can be done in any namespace, it just has to satisfy the conditions outlined below:

operator()() : a method for executing the nullary function object.
typedef result_type : a typedef to the return type of the operator.

Usage

Use with the compile time concept check whenever you wish to check for a nullary function object input. For example, the Thread class (ecl_threads) utilises this in a similar way to that outlined below:

template<typename F>
Thread(F function) {
    compile_time_concept_check(NullaryFunctionConcept<F>);
}