[cl-gd-devel] thread safety in cl-gd

[Alain Picard]

Dear all,

I'm wondering if cl-gd has been thoroughly tested for
thread safety?  I've experienced a couple of segfaults
here and there, apparently at random, in libgd.

Cursory inspection of the code seems to suggest, for instance,
that *transfomers* is not safe; the only references to this variable
I see are in specials.lisp: 
(defvar *transformers* nil
  "Stack of currently active transformer objects.")

and in WITH-TRANFORMATION, which does not create a new binding
for *transformers*, but rather just pushes a new transformation
onto the global *transformers*.

Am I reading this right?  It seems to me that two different
lispworks threads could run in such a way so that 1 thread
inadvertently starts running with transformers that another thread
establishes then gets swapped out.


Comments?

                                Alain Picard

 


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