* Re: modules and C
@ 2007-03-22 0:17 dsmich
2007-03-23 0:19 ` modules and C,C++ David Fang
0 siblings, 1 reply; 4+ messages in thread
From: dsmich @ 2007-03-22 0:17 UTC (permalink / raw)
To: David Fang; +Cc: guile-user
---- David Fang <fang@csl.cornell.edu> wrote:
> Hi,
> I'm having a bit of trouble using a symbol I defined in C from a
> module:
....
> What do I need to do to export my scm_c_define_gsubr'd
> functions to the module? Must I wrap them into another module in C, and
> use-module it? (Would I expect the same problem with mixing
> load-extensions with modules?)
>
> I've been reading the manuals and info on the module's sections and didn't
> find a satisfactory answer. (Is this a 'quirk?') What basic concept(s)
> am I missing here? Thanks in advance!
You will want to read about scm_c_export() and scm_c_call_with_current_module in http://www.gnu.org/software/guile/manual/html_node/Dynamic-Linking-and-Compiled-Code-Modules.html
and http://www.gnu.org/software/guile/manual/html_node/Accessing-Modules-from-C.html
-Dale
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: modules and C
@ 2007-03-23 7:01 Marco Maggi
0 siblings, 0 replies; 4+ messages in thread
From: Marco Maggi @ 2007-03-23 7:01 UTC (permalink / raw)
To: guile-user
"David Fang" wrote:
> What do I need to do to export my scm_c_define_gsubr'd
> functions to the module?
YMMV. This is what I do:
1. write a C module with its own initialisation function,
let's say that the module's file is "module.c" :
/* C module */
#include <libguile.h>
/* module functions here */
void
my_module_init (void)
{
}
/* end of module */
put the init function in an internal header file:
void my_module_init (void);
2. wrap all the Scheme interface function declarations
into SCM_DEFINE: for a function with a prototype:
extern SCM my_scheme_func (SCM arg1, SCM arg2);
declared in a header file, I write in the body of the
module:
#undef SFN
#define SFN "my-scheme-func"
SCM_DEFINE(my_scheme_func, SFN,
2, 0, 0, (SCM arg1, SCM arg2), "")
{
SCM s_result;
/* do something with 'arg1' and 'arg2' */
return s_result;
}
the symbol SFN is defined to be the name of the
Scheme procedure: that way the name is available
in the function's body for calls to 'scm_error()',
for example:
/* to throw a 'wrong-type-arg' error */
if (error_condition)
scm_error(scm_arg_type_key, SFN,
"error message",
SCM_BOOL_F, SCM_BOOL_F);
3. in the body of the module initialisation function
put an include for a ".x" file:
void
my_module_init (void)
{
/* other init stuff */
#ifndef SCM_MAGIC_SNARFER
# include "module.x"
#endif
}
4. before compiling: preprocess the "module.c" file
with the Guile snarfer program; I use a rule in
the Makefile, something like this
.SECONDARY: %.x
GUILE_SNARF = guile-snarf
%.x : %.c
$(GUILE_SNARF) $(@) $(<) $(INCLUDES)
%.o : %.c $.x
the ".x" file holds the function invocations
required to define the functions from "module.c"
something like:
scm_c_define_gsubr(s_my_scheme_func, 2, 0, 0,
(SCM (*)()) my_scheme_func); ;
when the snarfer processes the file the:
#include "module.x"
is excluded, but it is included when the compiler
does its job;
now you can use 'scm_c_call_with_current_module()'
and invoke the initialisation function.
--
Marco Maggi
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^ permalink raw reply [flat|nested] 4+ messages in thread
* modules and C
@ 2007-03-21 22:57 David Fang
0 siblings, 0 replies; 4+ messages in thread
From: David Fang @ 2007-03-21 22:57 UTC (permalink / raw)
To: guile-user
Hi,
I'm having a bit of trouble using a symbol I defined in C from a
module:
In a .cc file, I've defined some_C_function(), and exposed it to
guile via scm_c_define_gsubr("some-C-function", ...), which is called upon
initialization as part of an inner_main() passed to scm_shell(). The
program loads up fine, and I'm able to interactively call
(some-C-function) in the interpreter.
In a .scm module file, I (define-module (foo bar)) and
(define-public (blah x) (some-C-function x)).
I run my program again (with a GUILE_LOAD_PATH to the new .scm),
guile> (use-modules (foo bar))
I see both 'some-C-function' and 'blah' are available procedures, but as
soon as I call (blah ...), I get "Unbound variable: some-C-function"
guile> blah
#<procedure blah (x)>
guile> some-C-function
#<primitive-procedure some-C-function>
guile> (blah 1)
Backtrace:
In current input:
5: 0* [blah <raw-chpsim-trace-stream>]
In ../../../../src/scm/foo/bar.scm:
48: 1 (some-C-function x)
which indicates that my C-wrapped functions aren't visible to the newly
defined module, even through they are present in the interpreter's
environment. What do I need to do to export my scm_c_define_gsubr'd
functions to the module? Must I wrap them into another module in C, and
use-module it? (Would I expect the same problem with mixing
load-extensions with modules?)
I've been reading the manuals and info on the module's sections and didn't
find a satisfactory answer. (Is this a 'quirk?') What basic concept(s)
am I missing here? Thanks in advance!
Fang
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^ permalink raw reply [flat|nested] 4+ messages in thread
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