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< title > The MPL Reference Manual: void_</ title >
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< h1 >< a class = "toc-backref" href = "./data-types-miscellaneous.html#id1585" > void_</ a ></ h1 >
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< div class = "section" id = "id1280" >
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< h3 >< a class = "subsection-title" href = "#synopsis" name = "synopsis" > Synopsis</ a ></ h3 >
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struct < a href = "./void.html" class = "identifier" > void_</ a >
{
typedef < a href = "./void.html" class = "identifier" > void_</ a > type;
};
template< typename T > struct is_void;
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< h3 >< a class = "subsection-title" href = "#description" name = "description" > Description</ a ></ h3 >
< p >< tt class = "literal" >< span class = "pre" >< a href = "./void.html" class = "identifier" > void_</ a ></ span ></ tt > is a generic type placeholder representing " nothing" .</ p >
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<!-- In many cases, returning ``void_`` from a metafunction to signal
an absence of the requested data leads to a simpler user code than
having a separate metafunction specifically for the purpose of
performing the corresponding check. -->
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#include < < a href = "../../../../boost/mpl/void.hpp" class = "header" > boost/mpl/void.hpp</ a > >
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< td >< div class = "copyright-footer" >< div class = "copyright" > Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</ div >
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