Re: Aieee! Need help with gmodule!

[Andrew Clausen <clausen alphalink com au>]

Todd Graham Lewis wrote:

> My apologies in advance that this is not a general-purpose GNOME question.
>
> I am trying to use gmodule in a project (www.dents.org for more info).
> I am compiling some shared objects which I hope to link into my system.
>
> When I run my test g_module program on one of my shared object files,
> I get the following error:
>
> % gmodule_test modules/constant_module.so
> ** ERROR **: modules/constant_module.so: ELF file's phentsize not the
>         expected size
> aborting...
> %
>
> Since I can find no docs on gmodule, I have no idea if I am doing anything
> at all right.  Would whoever in this crowd is knowledgeable concerning
> gmodule mind looking this over and offering me what advice they can?
>
> I compile my objects this way:
>
>         gcc -shared  -fpic -DPIC -c \
>                 `/opt/gnome/bin/glib-config --cflags` -I.. \
>                 $file -o ${file%.c}.so

You need to do:

`glib-config gmodule --cflags`

Although it makes no difference for now (I don't know what platform you're using
though...)

What did you link with?  You certainly need `glib-config gmodule --libs`, for the
-rdynamic switch.

> Here is the output of nm on such an object:
>
>          U _GLOBAL_OFFSET_TABLE_
>          U _IO_stderr_
> 00000044 T dents_module_add_zone
> 0000014c T dents_module_answer
> 00000114 T dents_module_destroy
> 000000cc T dents_module_drop_zone
> 00000000 T dents_module_init
> 00000000 D dents_module_name
> 00000084 T dents_module_reload_zone
>          U fprintf
> 00000000 t gcc2_compiled.
>
> and here's my loader program:
>
> START
> #include <glib.h> /* gmodule */
> #include <gmodule.h> /* gmodule */
> #include <sys/stat.h> /* stat */
> #include <unistd.h> /* stat */
> #include <stdio.h> /* printf */
> #include "dents_module.h" /* struct dents_resolver_module */
>
> int main(int argc, char *argv[])
> {
>         /* We just want to load up a module and
>         call its answer routine. */
>
>         char *module_file_name;
>         struct dents_resolver_module my_mod;
>         GModule *module = NULL;
>         int (*my_func)();
>         unsigned int result;
>
>         if(argc!=2){
>                 fprintf(stderr, "%u is not 2!  Need one argument.\n", argc);
>                 exit(-1);
>         }
>
>         module_file_name=argv[1];
>
>         fprintf(stderr, "module file name is %s.\n", module_file_name);
>         if(g_module_supported()){
>                 module = g_module_open (module_file_name, G_MODULE_BIND_LAZY);
>                 if(!module){
>                         fprintf(stderr, "Aiee, module == NULL!\n");
>                         g_error(g_module_error());
>                 }
>         }
>
>         if (module && g_module_symbol (module, "dents_module_init", my_func)) {
>                 result=my_func();
>                 fprintf(stderr, "module init returned %u.\n", result);
>                 g_module_make_resident (module);
>         }
>
>         if (!my_func){
>                 g_warning ("Failed to load module \"%s\": %s",
>                         module ? module_file_name : module_file_name,
>                         g_module_error ());
>                 if (module) {
>                         g_module_close (module);
>                 }
>         }
> }
> END

That code looks pretty much right to me.

Andrew Clausen