[Solved] Raise compilation errors

Max13

Hi,

Is there a way to simply raise compilation errors?
For example, in a template class, if I only want to accept pointers type, how can I raise a compilation errors to prevent the user to instantiate the template class with a static type? (Or the contrary)

I'm looking for doing something like "qMetaTypeId":http://qt-project.org/doc/qt-5/qmetatype.html#qMetaTypeId which raises an error if the type isn't registered, do you guys have an idea?

Thanks.

[andreyc: I moved it to C++ Gurus. I think the question is more about C++ then about Desktop development]

andreyc

If you use C++ 11 then here is an example
@
/** http://www.cplusplus.com/reference/type_traits/

http://en.cppreference.com/w/cpp/language/static_assert
g++ -std=c++11 -o test test.cpp
*/

#include <iostream>
#include <type_traits>

template <class T>
void test(T a, T b)
{
static_assert(std::is_pointer<T>::value, "Test requires pointers");
auto c = b;
b = a;
a = c;
}

class A
{
public:
A() {}
~A() {}
};

int main() {
std::cout << std::boolalpha;
std::cout << "is_pointer:" << std::endl;
std::cout << "int: " << std::is_pointer<int>::value << std::endl;
std::cout << "int*: " << std::is_pointer<int*>::value << std::endl;
std::cout << "int**: " << std::is_pointer<int**>::value << std::endl;
std::cout << "int()(int): " << std::is_pointer<int()(int)>::value << std::endl;

int* pa = nullptr;
int* pb = nullptr;
test(pa, pb);

A* paA = nullptr;
A* pbA = nullptr;
test(paA, pbA);

A aA;
A bA;
test(&aA, &bA);
test(aA, bA);

int a = 0;
int b = 10;
test(a, b);

return 0;
}
@

Max13

[quote author="andreyc" date="1401231833"]http://en.cppreference.com/w/cpp/language/static_assert[/quote]

Oh thanks ! I didn't know about static_assert.

There also are: Q_STATIC_ASSERT(condition) and Q_STATIC_ASSERT_X(bool, message)