C++ Coding Standard Specification - CERN

C++ Coding Standard
Specification
3 Coding Version/Issue: 1.1/5
3.3.2 Constructor Initializer Lists
CL6
Initialise in the class constructors all data members.
And if you add a new data member, don’t forget to update accordingly all constructors,
operators and the destructor.
CL7
Let the order in the initializer list be the same as the order of declaration in the header file: first
base classes, then data members.
It is legal C++ to list initializer in any order you wish, but you should list them in the same
order as they will be called.
The order in the initializer list is irrelevant to the execution order of the initializers. Putting
initializers for data members and base classes in any order other than their actual
initialization order is therefore highly confusing and can lead to errors. A data member could
be accessed before it is initialized if the order in the initializer list is incorrect.
Virtual base classes are always initialized first, then base classes, data members, and finally
the constructor body for the most derived class is run.
Example:
class Derived : public Base { // Base is number 1
public:
explicit Derived(int i);
Derived();
};
private:
int jM; // jM is number 2
Base bM; // bM is number 3
Derived::Derived(int i) : Base(i), jM(i), bM(i) {
// Recommended order 1 2 3
}
// Empty
Source CXX-35, CXX-36
Status Majority
Not Common for CMS (will be OK in the future)
page 18
FINAL