Eliot, Ok, I'm chewing on that :) Thanks. Bill ________________________________ From: pharo-project-bounces@lists.gforge.inria.fr [pharo-project-bounces@lists.gforge.inria.fr] on behalf of Eliot Miranda [eliot.miranda@gmail.com] Sent: Sunday, March 25, 2012 3:46 PM To: Pharo-project@lists.gforge.inria.fr Subject: Re: [Pharo-project] FFI error message: Heisenbug On Sun, Mar 25, 2012 at 9:36 AM, Schwab,Wilhelm K <bschwab@anest.ufl.edu<mailto:bschwab@anest.ufl.edu>> wrote: I'm working on GSL+callbacks, and have hit a genuine Heisenbug - the behavior changes depending on when/where I break and/or step over or into code. Callbacks are getting hit successfully(!!!) but there is one function that crashes, unless I step over the call, in which case I get an error. In particular, if I step far enough into things to see the call, calling gsl_multifit_fdfsolver_set() is raising an error (vs. crashing if I don't look<g>) that says 'No module to load address from'. Anybody know what that means? I'm using the CogVM on Ubuntu Lucid. That's the error associated with FFIErrorNoModule, see ExternalFunction class>initializeErrorMessages. An FFI call will fail with this when it can't find the call address in the first method literal (or when doing ExternalFunction>invokeWithArguments and the receiver doesn't have a call address). Bill -- best, Eliot