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Subject: Re: scm_defined_p(sym, env)
Date: Tue, 23 Aug 2011 13:54:00 +0200
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To: Richard Shann <richard.shann@virgin.net>
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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
> 

>