48 lines
1.3 KiB
Plaintext
48 lines
1.3 KiB
Plaintext
[section boost/python/pointee.hpp]
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[section Introduction]
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<boost/python/pointee.hpp> introduces a traits metafunction `template pointee<T>` that can be used to extract the "pointed-to" type from the type of a pointer or smart pointer.
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[endsect]
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[section Class template `pointee`]
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`pointee<T>` is used by the [link high_level_components.boost_python_class_hpp.class_template_class_t_bases_hel `class_<...>`] template to deduce the type being held when a pointer or smart pointer type is used as its HeldType argument.
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``
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namespace boost { namespace python
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{
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template <class T> struct pointee
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{
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typedef T::element_type type;
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};
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// specialization for pointers
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template <T> struct pointee<T*>
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{
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typedef T type;
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};
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}
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``
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[endsect]
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[section Examples]
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Given a 3rd-party smart pointer type `smart_pointer<T>`, one might partially specialize `pointee<smart_pointer<T> >` so that it can be used as the HeldType for a class wrapper:
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``
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#include <boost/python/pointee.hpp>
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#include <boost/python/class.hpp>
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#include <third_party_lib.hpp>
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namespace boost { namespace python
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{
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template <class T> struct pointee<smart_pointer<T> >
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{
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typedef T type;
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};
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}}
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BOOST_PYTHON_MODULE(pointee_demo)
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{
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class_<third_party_class, smart_pointer<third_party_class> >("third_party_class")
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.def(...)
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...
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;
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}
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``
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[endsect]
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[endsect]
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