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Re: scm_defined_p(sym, env)
From: |
Richard Shann |
Subject: |
Re: scm_defined_p(sym, env) |
Date: |
Tue, 23 Aug 2011 14:26:31 +0100 |
I didn't find the SCM_UNBNDP() that you mention but since mailing the
list I stumbled on SCM_UNDEFINED and tried
if(opt==SCM_UNDEFINED) ...
and that seems to work.
So (unless I am doing something bad) I think I am back on course -
thanks!
Richard
On Tue, 2011-08-23 at 13:54 +0200, address@hidden wrote:
> On Tue, Aug 23, 2011 at 12:36:44PM +0100, Richard Shann wrote:
> > I have defined a function with one needed and one optional arg, using
> >
> > scm_c_define_gsubr (name, 2, 0, 0, callback);
> >
> > in my function I need to test if the second argument is present, it
> > looks like I need
> >
> > scm_defined_p(sym, env)
> >
> > but, if so, how do I find the value of env for the top-level
> > environment?
>
> Not shure I understand you here, Richard. Where would sym come from?
> If your function looks like this:
>
> (richards-function required-param an-optional-param)
>
> thane your c function needs exactly two parameters:
>
> ricks_c_func(SCM req, SCM opt) {
>
> ...
>
> if (!SCM_UNBNDP (opt)) {
> /* opt wasn't provided, so do something here */
> }
>
> ...
>
> }
>
>
> Does that help?
>
> Cheers, Ralf Mattes
>
> > Richard Shann
> >
>
> >