You were close with ((dynamic-require 'hw 'hw))
but you're missing a quote:
((dynamic-require ''hw 'hw))
When you make "base.c" as
raco ctool --c-mods base.c hw.rkt
then it's like
(module hw racket/base
(provide hw)
(define (hw) (displayln "Hello, world!")))
at a REPL, and you'd require that module with
(require 'hw)
When using `dynamic-require`, the module name must be quoted, which
means an odd-looking extra quote in this case:
(dynamic-require ''hw ....)
Along similar lines, instead of
v = scheme_intern_symbol("hw");
scheme_namespace_require(v);
you'd need to use
v = scheme_make_pair(scheme_intern_symbol("quote"),
scheme_make_pair(scheme_intern_symbol("hw"),
scheme_make_null()));
scheme_namespace_require(v);
The enclosed "hw.c" shows how to use scheme_dynamic_require(), which is
similar and probably what you want.
The documentation for `raco ctool --c-mods` doesn't explain what it
does with a file like "hw.rkt" --- i.e., that it's like declaring a
module 'hw, and that any connection to a "hw.rkt" file is discarded ---
and I'll work on the documentation.
At Wed, 30 Mar 2016 19:02:24 -0700 (PDT), Anthony Sterrett wrote:
> I appear to be swimming upstream. There are all sorts of tutorials and
> references for *extending* Racket with C, but precious little about
> *embedding* it. Unfortunately, I require the latter.
>
> I have a file hw.rkt with the following contents:
>
> #lang racket/base
>
> (provide hw)
>
> (define (hw)
> (displayln "Hello, world!"))
>
> I would like to write a C program which uses an embedded Racket runtime to
> load and call the (hw) procedure.
>
> Resources I've found so far:
>
> * http://docs.racket-lang.org/inside/embedding.html#%28part._3m_.Embedding%29
>
> I have built and run the example program successfully, and thereby learned
> how
> to call a procedure provided by racket/base. I assume the same pattern
> applies
> for any library compiled with raco ctool. My efforts to apply this knowledge
> to hw.rkt have so far failed me, though.
>
> * http://docs.racket-lang.org/raco/c-mods.html
>
> This page appears to say that what I want to do is *possible*, and tells me
> how to compile hw.rkt to a C file (which I have successfully done), but not
> how to use it afterward.
>
> I have asked this question on Stack Overflow and on Reddit, to no avail:
>
> http://stackoverflow.com/q/36286921/2209270
>
> https://www.reddit.com/r/Racket/comments/4ci29u/call_userprovided_racket_proced
> ure_from_c_xpost/
>
> The Stack Overflow link also includes what I've tried so far, and the error
> messages I've received for my efforts.
>
> An ideal answer would provide an example program in C that I could copy,
> compile, and run. An acceptable answer would tell me which C functions I'm
> supposed to use, and how to invoke them.
>
> I will appreciate any assistance you're able to render. Thank you.
>
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hw.c
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