[plt-scheme] scheme/foreign issues - string conversion and DrScheme crashing

From: Ben Simon (benjisimon at gmail.com)
Date: Thu Dec 25 16:32:58 EST 2008

On Thu, Dec 25, 2008 at 3:56 PM, Eli Barzilay <eli at barzilay.org> wrote:

> On Dec 25, Ben Simon wrote:
> > I started in on it, and I've run into two major issues:
> ...
>  bytes->string/utf8: string not well-formed UTF-8 encoding: #"0\344\22"
> >
> > Any thoughts as to why *mysql_error* is returning back a string scheme is
> > choking on?
> It's probably best to change the type to _bytes, then see what the
> actual char* contents is.

Good to know.  Perhaps the fact that mysql_error() is returning garbage is
related to the system crashing. Hmmm, maybe something is just massively

> > 2) DrScheme has been crashing nearly constantly since I started
> > working on this.

> The most common cause of this is a bad memory reference, usually
> because mzscheme uses a moving GC (by default).  Some things that you
> can do to verify this are adding `collect-garbage' in various places
> (maybe even a thread that keeps triggering GCs), and trying to run the
> code with the CGC executables.  (You can get them as part of the
> "Full" distribution from the nightly builds.)

Thanks for the tips.

> Another thing to verify is that you don't call the close function
> twice on aa handler or something similar.

I added a print statement right before close was called - and the system
crashed before it even got that far. Still, good to know.

> Other than that -- yes, life in the (unsafe!) world can be hard...

Yeah, you can say that again :-).


Have an idea for software?  I can make it happen -
My Blog: http://benjisimon.blogspot.com
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