Qt and stl templates

Milosz

Hi everybody,
I'd like to make a template to test a certain number of containers (both stl and Qt)
The declaration for Qt is:

template<typename Tp, template<typename> typename Container>
class ContainerTest
{
public:
	void test()
	{
		...
	}
private:
	Container<Tp> container;
};

and sample specializations :

    ContainerTest<qint16, QList> l(55);
    ContainerTest<qreal, QVector> li(55);
    ContainerTest<uint16_t, QVector> la(55);
    ContainerTest<int32_t, QList> lb(55);

Unfortunatelly this template cannot be used for stl templates like vector or list. The proper one is:

template<typename Tp, template<typename, typename=allocator<Tp>> typename Container>
class ContainerTest
{
...
};

and sample specializations :

    ContainerTest<qint16, vector> l(55);
    ContainerTest<qreal, list> li(55);

Can anyone show a solution path with just one template for both Qt and stl templates?

Thanks in advance

ChrisW67

Since the second argument to the std::vector or std::list template has a default you can use C++11 variadic templates:

#include <QCoreApplication>
#include <QVector>
#include <QList>
#include <vector>
#include <list>

template<typename Tp, template<typename...> typename Container>
class ContainerTest
{
public:
        void test()
        {
        }
private:
        Container<Tp> container;
};


int main(int argc, char **argv) {
        QCoreApplication app(argc, argv);

        ContainerTest<uint32_t, QVector> la;
        ContainerTest<uint32_t, QList>   lb;
        ContainerTest<uint32_t, std::vector> lc;
        ContainerTest<uint32_t, std::list>   ld;

        return 0;
}

This compiles fine for me with GCC 9.4.0 and Qt 5.12.8. Does it scratch your itch?

Milosz

It is great,
Thank you

Best regards