Hi,
How do you get at a static function from within a C extension? I tried
this snippet where I attempt to use flo_plus from numeric.c:
/* foo.c */
#include <ruby.h>
extern VALUE flo_plus(VALUE, VALUE);
static VALUE foo_test(VALUE x, VALUE y){
return flo_plus(x, y);
}
void Init_foo(){
VALUE cFoo = rb_define_class("Foo", rb_cObject);
rb_define_method(cFoo, "test", foo_test, 2);
}
# test.rb
$:unshift Dir.pwd
require 'foo'
f = Foo.new
f.test
This result is:
ruby: symbol lookup error:
/home/djberge/programming/ruby/extensions/foo.so: undefined symbol:
flo_plus
I tried linking explicitly against -lruby but that didn't help.
Regards,
Dan
Daniel Berger wrote:
Hi,
How do you get at a static function from within a C extension? I tried
this snippet where I attempt to use flo_plus from numeric.c:
/* foo.c */
#include <ruby.h>
extern VALUE flo_plus(VALUE, VALUE);
static VALUE foo_test(VALUE x, VALUE y){
return flo_plus(x, y);
}
void Init_foo(){
VALUE cFoo = rb_define_class("Foo", rb_cObject);
rb_define_method(cFoo, "test", foo_test, 2);
}
# test.rb
$:unshift Dir.pwd
require 'foo'
f = Foo.new
f.test
This result is:
ruby: symbol lookup error:
/home/djberge/programming/ruby/extensions/foo.so: undefined symbol:
flo_plus
I tried linking explicitly against -lruby but that didn't help.
Regards,
Dan
Where is 'flo_plus' defined?
I could be wrong, but I believe the entire purpose of a static function is to _not_ be get at able from other code (sort of like private in ruby).
···
On Aug 1, 2006, at 8:10 PM, Daniel Berger wrote:
Hi,
How do you get at a static function from within a C extension? I tried
this snippet where I attempt to use flo_plus from numeric.c:
Hello !
This result is:
ruby: symbol lookup error:
/home/djberge/programming/ruby/extensions/foo.so: undefined symbol:
flo_plus
I tried linking explicitly against -lruby but that didn't help.
By the way, if you're interested to know which symbols are exported
from a library, just do
nm -D /usr/lib/library.so
A look to that on my computer shows no references to flo_plus, only:
nm -D /usr/lib/libruby1.8.so | grep flo
U flock
U floor
0000000000057ef0 T rb_float_new
Cheers
Vincent
Timothy Hunter wrote:
Daniel Berger wrote:
> Hi,
>
> How do you get at a static function from within a C extension? I tried
> this snippet where I attempt to use flo_plus from numeric.c:
>
> /* foo.c */
> #include <ruby.h>
>
> extern VALUE flo_plus(VALUE, VALUE);
>
> static VALUE foo_test(VALUE x, VALUE y){
> return flo_plus(x, y);
> }
>
> void Init_foo(){
> VALUE cFoo = rb_define_class("Foo", rb_cObject);
> rb_define_method(cFoo, "test", foo_test, 2);
> }
>
> # test.rb
> $:unshift Dir.pwd
> require 'foo'
> f = Foo.new
> f.test
>
> This result is:
>
> ruby: symbol lookup error:
> /home/djberge/programming/ruby/extensions/foo.so: undefined symbol:
> flo_plus
>
> I tried linking explicitly against -lruby but that didn't help.
>
> Regards,
>
> Dan
>
>
>
Where is 'flo_plus' defined?
In numeric.c. Note that it *builds* fine, it just doesn't *run*.
Regards,
Dan
Vincent Fourmond wrote:
By the way, if you're interested to know which symbols are exported
from a library, just do
nm -D /usr/lib/library.so
A look to that on my computer shows no references to flo_plus, only:
nm -D /usr/lib/libruby1.8.so | grep flo
U flock
U floor
0000000000057ef0 T rb_float_new
In Ruby, the functions that are intended for use by extensions start with the prefix "rb_" and are declared in either ruby.h or intern.h. Since flo_plus doesn't start with "rb_" it isn't intended to be available to extensions.
Daniel Berger wrote:
Timothy Hunter wrote:
Daniel Berger wrote:
Hi,
How do you get at a static function from within a C extension? I tried
this snippet where I attempt to use flo_plus from numeric.c:
/* foo.c */
#include <ruby.h>
extern VALUE flo_plus(VALUE, VALUE);
static VALUE foo_test(VALUE x, VALUE y){
return flo_plus(x, y);
}
void Init_foo(){
VALUE cFoo = rb_define_class("Foo", rb_cObject);
rb_define_method(cFoo, "test", foo_test, 2);
}
# test.rb
$:unshift Dir.pwd
require 'foo'
f = Foo.new
f.test
This result is:
ruby: symbol lookup error:
/home/djberge/programming/ruby/extensions/foo.so: undefined symbol:
flo_plus
I tried linking explicitly against -lruby but that didn't help.
Regards,
Dan
Where is 'flo_plus' defined?
In numeric.c. Note that it *builds* fine, it just doesn't *run*.
Regards,
Dan
I see. Since flo_plus has static linkage in numeric.c you can't call it from your extension. It builds okay because you supplied a declaration for it, and it links okay because Linux does lazy linking (that is, external symbols aren't resolved until the .so gets loaded), but it won't run because there's no external definition of flo_plus to match your external reference.
You'll have to use rb_funcall to call "+".