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Local type as template arguments in C++ [duplicate]

This question already has answers here: Using local classes with STL algorithms 开发者_如何学运维 (2 answers) Closed 9 years ago.

This is my code

#include <vector>
template <typename T, template<typename> class C = std::vector >
struct FooBar
{
   /*codez*/
};
template<typename T>
struct Global{};

int main()
{
   struct Local{};  
   FooBar<Local,Global> k;
}

This is the error that I get

template argument for ‘template<class T, template<class> class C> struct FooBar’ uses local type ‘main()::Local’

Which part of the standard says that this is wrong? I am using gcc 4.5.1. How can make this code work?


Which part of the standard says that this is wrong?

That would be §14.3.1/2 from the 2003 C++ Standard:

A local type, a type with no linkage, an unnamed type or a type compounded from any of these types shall not be used as a template-argument for a template type-parameter.


How can make this code work?

Don't use a local type as a template argument.

Note that this restriction has been lifted in C++11, so using that language standard you are able to use a local type as a template argument.


14.3.1/2

A local type, a type with no linkage, an unnamed type or a type compounded from any of these types shall not be used as a template-argument for a template type-parameter.

Try compiling your code with -std=c++0x option (gcc 4.5.1). C++0x lifts the restriction and so you can use a local type as template argument.

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