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+---- Thread: Rule 0-1-3/0-1-4/0-1-5 and (template) class members (/showthread.php?tid=1309)
Rule 0-1-3/0-1-4/0-1-5 and (template) class members - grunwald - 01-02-2017
Do these rules apply to class members?
If so, do they apply to instances of template class members?
Code:
template
class C {
T member1; // never used; compliant with 0-1-3?
T member2; // C::member2 is used but C::member2 is not; compliant with 0-1-3?
typedef T Unused; // typedef never used: non-compliant with 0-1-5.
typedef T X; // C::X is used but C::X is not; compliant with 0-1-5?
void call() { // only instantiated for C
use(static_cast(member2));
}
};
int main() {
C().call();
C();
}The same question also applies to 0-1-4.
For 0-1-10 the situation is different, as class template member functions only get instantiated if they actually used. Thus C::call() is compliant with 0-1-10. A completely unused class template member function would be non-compliant with Rule 14-7-1.
Re: Rule 0-1-3/0-1-4/0-1-5 and (template) class members - misra cpp - 10-07-2017
The basic answer to all these queries is that every definition in the program must be used somewhere, or conversely, it should not be possible to remove a definition from the code and still have the program compile.
So for a template class, each member of the class must be used by at least one instantiation of the template.