Am 26.04.2006 um 09:35 schrieb James Bielman:
You seem to be going to a fair bit of trouble here to reproduce what
the CFFI :STRING type does automatically... why not something like:
(defcfun ("Tcl_EvalFile" tcl-eval-file) :int
(interp :pointer)
(filename :string))
(defcfun ("Tcl_Eval" tcl-eval) :int
(interp :pointer)
(script :string))
instead of mucking about with low-level stuff like null terminators.
There is also WITH-FOREIGN-STRING that encapsulates this pattern in a
macro when you don't want to use the :STRING type.
Thx for pointing out. I took my approach straight from the example cl-
opengl as done by - Luis, I think... ;-)
Also, one technique I've found very handy when writing bindings for
APIs that are consistent about returning error codes is to define a
special result type and hang a translator on it, to get automatic
error checking (untested, caveat executor):
;; Now TCL-EVAL-FILE and TCL-EVAL can return a TCL-ERROR instead of
;; :INT and the translator will get called on the return value.
(defctype tcl-error :int)
(defmethod translate-from-foreign (value (type (eql 'tcl-error)))
(unless (zerop value) ;; or whatever
(error "got some tcl error ~D..." value))
value)
Superb. Works like a charm. Thanks!
Apart from any other TCL-specific issues like Yaroslav mentioned,
perhaps the TCL output stream is buffered and needs to be flushed
somehow?
Actually I had a typo in the source (missing paranthesis) that
prevented the call of the Tcl function al all - so I was seeing the
foreign ptr addresses as results ... That's why I was a bit surprised.
Now I can call Tcl_Eval and do get the message as defined via the
puts command on the standard output stream.
James
Thanks again!
Frank
_______________________________________________
cffi-devel mailing list
cffi-devel@common-lisp.net
http://common-lisp.net/cgi-bin/mailman/listinfo/cffi-devel
