Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

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is_pointer

template <class T>
struct is_pointer : public true_type-or-false_type {};

Inherits: If T is a (possibly cv-qualified) pointer type (includes function pointers, but excludes pointers to members) then inherits from true_type, otherwise inherits from false_type.

C++ Standard Reference: 3.9.2p2 and 8.3.1.

Header: #include <boost/type_traits/is_pointer.hpp> or #include <boost/type_traits.hpp>

Examples:

is_pointer<int*> inherits from true_type.

is_pointer<char* const>::type is the type true_type.

is_pointer<int (*)(long)>::value is an integral constant expression that evaluates to true.

is_pointer<int (MyClass::*)(long)>::value is an integral constant expression that evaluates to false.

is_pointer<int (MyClass::*)>::value is an integral constant expression that evaluates to false.

is_pointer<T>::value_type is the type bool.

[Important] Important

is_pointer detects "real" pointer types only, and not smart pointers. Users should not specialise is_pointer for smart pointer types, as doing so may cause Boost (and other third party) code to fail to function correctly. Users wanting a trait to detect smart pointers should create their own. However, note that there is no way in general to auto-magically detect smart pointer types, so such a trait would have to be partially specialised for each supported smart pointer type.


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