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From: nagle@well.UUCP (John Nagle)
Newsgroups: comp.lang.c++
Subject: Re: Allowing only one instantiation of a class
Message-ID: <14092@well.UUCP>
Date: 13 Oct 89 17:13:49 GMT
References: <672@suntops.Tops.Sun.COM>
Reply-To: nagle@well.UUCP (John Nagle)
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 19

In article <672@suntops.Tops.Sun.COM> rdas@hatter.Tops.Sun.COM (Robin Das) writes:
>
>How do you allow only one instantation of a class across a system?

     Well, you could write

      class onceonly {
	static unsigned char instances = 0;
	...
	onceonly()
	{	assert(instances==0);
		instances++;
	}
      };

which ought to get the idea across.   There's no way to express the idea
in a way that the compiler will enforce it.

					John Nagle