View source for cpp/types/NULL

===Notes===
In C, the macro {{tt|NULL}} may have the type {{c/core|void*}}, but that is not allowed in C++ because null pointer constants cannot have that type.

Some implementations define {{tt|NULL}} as the compiler extension {{tt|__null}} with following properties:
* {{tt|__null}} is equivalent to a zero-valued integer literal (and thus compatible with the C++ standard) and has the same size as {{c/core|void*}}, e.g. it is equivalent to {{c|0}}/{{c|0L}} on [[cpp/language/types#Data models|ILP32/LP64]] platforms respectively;
* conversion from {{tt|__null}} to an arithmetic type, including the type of {{tt|__null}} itself, may trigger a warning.