Path: utzoo!news-server.csri.toronto.edu!rutgers!hsdndev!spdcc!tauxersvilli!alphalpha!nazgul
From: nazgul@alphalpha.com (Kee Hinckley)
Newsgroups: comp.windows.x
Subject: Re: C++ and X: Member-Functions as Callbacks
Message-ID: <1991Mar10.021700.19538@alphalpha.com>
Date: 10 Mar 91 02:17:00 GMT
References: <1991Mar9.123358.14352@csn.org>
Organization: asi
Lines: 29

In article <1991Mar9.123358.14352@csn.org> rink@tramp.colorado.edu (Jeff) writes:
>
>
>Howdy.
>Help requested from C++ and X gurus:
>
>
>	I am trying to set up a callback for an X widget.  I would LIKE
>	to have the callback be a member-function of a C++ class.
>	An example:

The only way you can make this work is to declare the member function
static.  Then it's up to you to figure out how to pass "this".  The
easiest way is in the the callback data, the second easiest is in
the widgets userData resource.  It would be nice if C++ allowed you
to then assign this and proceed normally, but....

If you want to do virtual functions, declare two callbacks, one static
and one virtual.  All the static one does is call the virtual one.

					-kee
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I'm not sure which upsets me more: that people are so unwilling to accept
responsibility for their own actions, or that they are so eager to regulate
everyone else's.