From 81c8af90ece8a05d238d12b6d20b658a2e0a30a4 Mon Sep 17 00:00:00 2001 From: Douglas Gregor Date: Wed, 12 Mar 2003 23:27:25 +0000 Subject: [PATCH] Import of BoostBook documentation for any, array, bind, function, ref, and signals libraries. [SVN r17866] --- doc/ref.xml | 222 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 222 insertions(+) create mode 100644 doc/ref.xml diff --git a/doc/ref.xml b/doc/ref.xml new file mode 100644 index 0000000..05942eb --- /dev/null +++ b/doc/ref.xml @@ -0,0 +1,222 @@ + + + + + + Jaakko + Järvi + + + Peter + Dimov + + + Douglas + Gregor + + + Dave + Abrahams + + + + 1999 + 2000 + Jaakko Järvi + + + + 2001 + 2002 + Peter Dimov + + + + 2002 + David Abrahams + + + + Permission to copy, use, modify, sell and distribute this + software is granted provided this copyright notice appears in + all copies. This software is provided "as is" without express + or implied warranty, and with no claim as to its suitability for + any purpose. + + + + A utility library for passing references to generic functions + + + +Boost.Ref + +
+ Introduction + + + + The Ref library is a small library that is useful for passing + references to function templates (algorithms) that would usually + take copies of their arguments. It defines the class template + boost::reference_wrapper<T>, + the two functions + boost::ref and + boost::cref that return + instances of boost::reference_wrapper<T>, and the + two traits classes + boost::is_reference_wrapper<T> + and + boost::unwrap_reference<T>. + + The purpose of + boost::reference_wrapper<T> is to + contain a reference to an object of type T. It is primarily used to + "feed" references to function templates (algorithms) that take their + parameter by value. + + To support this usage, + boost::reference_wrapper<T> provides an implicit + conversion to T&. This usually allows the function + templates to work on references unmodified. + + boost::reference_wrapper<T> is + both CopyConstructible and Assignable (ordinary references are not + Assignable). + + The expression boost::ref(x) + returns a + boost::reference_wrapper<X>(x) where X + is the type of x. Similarly, + boost::cref(x) returns a + boost::reference_wrapper<X const>(x). + + The expression + boost::is_reference_wrapper<T>::value + is true if T is a reference_wrapper, and + false otherwise. + + The type-expression + boost::unwrap_reference<T>::type is T::type if T + is a reference_wrapper, T otherwise. +
+ + +
+ + + + + Contains a reference to an object of type + T. + + + + reference_wrapper + is primarily used to "feed" references to function templates + (algorithms) that take their parameter by value. It provides + an implicit conversion to + T&, which usually allows + the function templates to work on references unmodified. + + + + + + + T& + + + Constructs a + reference_wrapper + object that stores a reference to + t. + + Does not throw. + + + + + The stored reference. + Does not throw. + + + + The stored reference. + Does not throw. + + + + A pointer to the object referenced by the stored reference. + Does not throw. + + + + + + + T& + + + reference_wrapper<T>(t) + + Does not throw. + + + + + T const& + + + reference_wrapper<T const>(t) + + Does not throw. + + + + + + + + Determine if a type T is an instantiation of reference_wrapper. + + The value static constant will be true iff the type T is a specialization of reference_wrapper. + + + + + + + + Find the type in a reference_wrapper. + + The typedef type is T::type if T is a reference_wrapper, T otherwise. + + + + +
+ + +
+ Acknowledgements + + + + ref and cref + were originally part of the Tuple library + by Jaakko Järvi. They were "promoted to boost:: status" by + Peter Dimov because they are generally useful. Douglas Gregor and + Dave Abrahams contributed + is_reference_wrapper and + unwrap_reference. +
+ + \ No newline at end of file