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The functions must have different type signatures, i.e. differ in the number or the types of their formal parameters (as in C++) or additionally in their return type (as in Ada). [9] Function overloading is usually associated with statically-typed programming languages that enforce type checking in function calls. An overloaded function is a ...
When a class template like equal_comparable is instantiated, the in-class friend definitions produce nontemplate (and nonmember) functions (operator functions, in this case). At the time the idiom was introduced (1994), the C++ language did not define a partial ordering for overloaded function templates and, as a result, overloading function ...
In the C++ Standard Library, several algorithms use unqualified calls to swap from within the std namespace. As a result, the generic std::swap function is used if nothing else is found, but if these algorithms are used with a third-party class, Foo, found in another namespace that also contains swap(Foo&, Foo&), that overload of swap will be used.
The previous section notwithstanding, there are other ways in which ad hoc polymorphism can work out. Consider for example the Smalltalk language. In Smalltalk, the overloading is done at run time, as the methods ("function implementation") for each overloaded message ("overloaded function") are resolved when they are about to be executed.
Often the compiler selects the overload to call based on the type of the input arguments or it fails if the input arguments do not select an overload. Older and weakly-typed languages generally do not support overloading. Here is an example of overloading in C++, two functions Area that accept different types:
C++ uses function overloading with various signatures. The practice of multiple inheritance requires consideration of the function signatures to avoid unpredictable results. Computer science theory, and the concept of polymorphism in particular, make much use of the concept of function signature.
The problem is that, while virtual functions are dispatched dynamically in C++, function overloading is done statically. The problem described above can be resolved by simulating double dispatch, for example by using a visitor pattern. Suppose the existing code is extended so that both SpaceShip and ApolloSpacecraft are given the function
Although name mangling is not generally required or used by languages that do not support function overloading, like C and classic Pascal, they use it in some cases to provide added information about a function. For example, compilers targeted at Microsoft Windows platforms support a variety of calling conventions, which determine the manner in ...