Path: utzoo!attcan!uunet!cs.utexas.edu!rutgers!apple!sun-barr!decwrl!ucbvax!bloom-beacon!ATHENA.MIT.EDU!swick
From: swick@ATHENA.MIT.EDU (Ralph R. Swick)
Newsgroups: comp.windows.x
Subject: Re: XtConvert & SetValues for floats
Message-ID: <8907260505.AA26883@LYRE.MIT.EDU>
Date: 26 Jul 89 05:05:04 GMT
References: <14000@lanl.gov>
Sender: daemon@bloom-beacon.MIT.EDU
Organization: DEC/MIT Project Athena
Lines: 15


> The initialize procedure assigns the correct default values, but when I
> try to do a set_values after realizing the widget on the float resource
> I get garbage (0).
...
> Is
> there something wierd about floats, or have I made a mistake in my code

Yeah, there's something wierd about floats.  If you try
to pass floats by value rather than by reference and assign
a float value to an arglist entry in one of the normal ways,
the C compiler will cleverly convert the float to a long.

You have to do some ugly stuff with unions to convince the
compiler not to convert the value when storing it in the arglist.