Re: Can singleton be owned by any object other than itself

From:

Greg Herlihy <greghe@mac.com>

Newsgroups:

comp.lang.c++

Date:

Fri, 20 Jun 2008 03:57:51 -0700 (PDT)

Message-ID:

<5309149c-78f8-43d2-8890-416fd06f3d84@z16g2000prn.googlegroups.com>

On Jun 20, 3:42 am, tech <naumansulai...@googlemail.com> wrote:

Is it ok to allow another object to own a singleton object, or is
this definitely a NO NO.
I have a utility class that i want to provide access to a whole group
of subobjects so i can make
this utility a singleton. But i was wondering if i can have it owned
by a top level object
which encompasses all the other subobjects(which would use the
singleton utility)
so there shouldn't be any refs to the handle floating around when the
top level is destroyed
and it would of course destroy the singleton.

In my experience, it's actually a very good idea to have a singleton
be a member variable of another singleton (whose life span encompasses
the life span of the member singleton). In this way, a C++ program can
ensure the orderly construction and destruction of its singletons.
Otherwise, it is much more difficult for a program to control the
order in which singletons are allocated and destroyed - making it much
more likely that a singleton will be destroyed before one of its
dependent singletons is destroyed.

Greg