Templates - T must support a specific Interface

[cpisztest]

Was there something in the new standard that allowed us to impose that limitation?

 

[Victor Bazarov]

Was there something in the new standard that allowed us to impose that limitation?

What is it that you would like done? If you just write your code so
that it uses that interface, the compilation will fail if such interface
is absent, for instance:

class Has_foo {
public:
void foo();
};

class No_foo {
public:
void bar();
};

template<class T> void Needs_foo(T* pObj) {
pObj->foo();
};

int main() {
Has_foo does;
No_foo doesnt;

Needs_foo(&does); // compiles OK
Needs_foo(&doesnt); // fails
}

And that has existed in C++ since 98.

V

 

[Jorgen Grahn]

What is it that you would like done? If you just write your code so
that it uses that interface, the compilation will fail if such interface
is absent, for instance:
....
And that has existed in C++ since 98.

Don't you think he's looking for "concepts"?

http://en.wikipedia.org/wiki/Concepts_(C++)

I never studied them, but I think Stroustrup spends some pages in the
latest "The C++ Programming Language" showing how you can do something
along those lines without language support.

/Jorgen