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// variadic function template
template<typename ...Params>
void fun(Params ...parameters)
{}
// instantiation declaration
template
void fun<int>(int v);
// pointers to functions that are instantiated from a variadic function
// template
void (*fp)(int) = fun;
void (*fp2)(int, double) = fun;
// template class having variadic function template member
template <typename T>
struct Demo
{
template<typename ...Params>
void mem(Params ...parameters)
{}
};
// instantiation declaration:
template
void Demo<char>::mem<int>(int v);
// pointers to functions that are instantiated from a variadic function
// template
void (Demo<char>::*mp)(int) = &Demo<char>::mem;
void (Demo<char>::*mp2)(int, double) = &Demo<char>::mem;
// explicitly obtain the address of the Demo::mem member expecting an int:
void (Demo<char>::*mp1)(int) =
//&Demo<char>::mem(int);
// error meesage: expected primary-expression before 'int'
&Demo<char>::mem<int>;
// OK
// a template class using perfect forwarding:
template<typename T>
struct Demo2
{
template<typename ...Args>
void mem(Args&&...args)
{}
};
// instantiation declaration:
template
// void Demo2<char>::mem<int>(int v);
// error: template-id 'mem<int>' for 'void Demo2<char>::mem(int)' does
// not match any template declaration
// void Demo2<char>::mem<typename ...Args>(Args &&...args);
// error: using 'typename' outside of template
// expected parameter pack before '...'
// parse error in template argument list
// template-id 'mem<<expression error> >' used as a declarator
// variable or field 'mem' declared void
// expected `;' before '(' token
void Demo2<char>::mem<int &&>(int &&);
// or: void Demo2<char>::mem(int &&);
// pointers to Demo2::mem:
//OK void (Demo2<char>::*mpd2)(int &&) = &Demo2<char>::mem;
void (Demo2<char>::*mpd2)(int &&) = &Demo2<char>::mem<int>; // ook OK
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