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Questions tagged [variadic-templates]

Variadic templates are templates that take a variable number of parameters.

Some programming languages, like D and C++ since with the C++11 standard, support templates that take a variable number of parameters. Variadic templates are useful in a number of situations, for example, defining type-safe heterogeneous containers such as tuples and expanded metaprogramming library facilities.

http://en.wikipedia.org/wiki/Variadic_templates

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compile error on variadic template function parameter

I'm trying to write some parameter wrapping helper code like below #include #include struct test{}; namespace ns { struct test{}; } template struct arg_wrapper; template<> struct arg_wrapper { …
summerlight
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Computing a function over variadic templates

I am trying to figure out which is the most idiomatic way implement a function over a variadic type list. For example, computing the maximum size of all the types. I understand there exist several approaches to accomplish such a task, but I would…
mavam
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C++11 std::tuple to std::array conversion causes variadic template crash

The following function, toArray, might one day convert a C++11 std::tuple into a C++11 std::array: #include #include template std::array toArray(std::tuple) { return…
user2023370
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How to program this with variadic templates?

I have never used variadic templates myself, but think I could need them now. Suppose I have a class class A { int Kern; template void func_a(int, double) const; template void func_b(double, double, char) const; template…
Walter
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Construct a variadic template of unsigned int recursively

I need a tricky thing in a C++ 2011 code. Currently, I have a metafunction of this kind : template static constexpr unsigned int myFunction() This function can generate number based on N and M. I would like to write…
Vincent
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Friend function with CRTP + enable_if is not working?

The following code does not compile and I don't know why: #include // Base class definition template class CRTP, typename T> class Base { // Friend function declaration public: …
Vincent
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std::tuple to member functions

I'm still trying to get the swing of metaprogramming, and I'm stumped. What's I'd like to do is create a class/struct/whatever, supply it a std::tuple and have it automatically generate member functions based on the object types in the tuple. The…
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How do I use values from an std::tuple as function arguments?

#include class Foo { public: Foo(int i, double d, const char* str) { } }; template class ObjectMaker { public: ObjectMaker(CtorArgTypes... ctorArgs) : m_ctorArgs(ctorArgs...) { } Foo*…
Mark
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Recursive metafunction using variadic templates

I am writing a meta function replace_type that is supposed to replace all matches of type X in a compound type C with Y. I am currently working on properly getting this to work with callables in C. This works: template replace_type< …
nikolas
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Variadic Template lambda expansion

I'm trying to implement a delegate class following Herb Sutter's Example. There is a sections in this article that duplicates several templates; one template for the number of arguments in the list (Example 7, lines 41 - 59)1. I'm trying to replace…
Jeremy W
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How do I change the number of template arguments supported by MSVC++'s std::tuple?

MSVC++ doesn't yet support variadic templates, so its standard library "fakes" these for classes like std::tuple through use of macros. I recently tried compiling one of my projects with the VC11 beta, and got this to show for…
Billy ONeal
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Reference counting with a generic intrusive pointer client

Introduction Peter Weinhart describes how to design a generic intrusive_ptr base class using CRTP, which may be used as follows: class foo : intrusive_base { // foo-specific code. }; This approach imposes the constraint that all foo…
mavam
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Wrap Loki::Typelist with C++11 variadic template

I am trying to avoid LOKI_TYPELIST_n macros, so I though I can write simple Loki::Typelist wrapper. template struct TYPELIST; template <> struct TYPELIST<> { typedef Loki::NullType Result; }; template
Dragomir Ivanov
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Nested template specialization depending on enclosing template parameters

template < int ...Indices> class T1 { template class T2; }; template template class T1::T2<_1, sizeof...(Indices)> {}; //^--error: non-type template argument depends on a template…
Buote Xu
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How can I get the first N elements of a tuple c++?

lets say I had a function like the following, how could I get the first n elements of a tuple? template void foo(Ts... ts){ std::tuple all_elements(ts...); auto first_elements = //the first N elements of the…
Sam Moldenha
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