[asterisk-dev] loading modules help

[Mark Michelson]

Boehm, Matthew wrote:
> Hello,
> 
> I’m trying to understand how the modules are loaded in asterisk. I can 
> see that every module has a “load_module” and “unload_module” function. 
> And I can see in main/loader.c in the load_dynamic_module() function the 
> call to dlopen() on the module.so file path.
> 
>  
> 
> But what I am not seeing is where the just-loaded-module’s “load_module” 
> function is called, which registers the module and its functions to the 
> main core lists.
> 
>  
> 
> Take, for example, app_mp3. I type “module load app_mp3.so” which calls 
> main/cli:handle_load(), which passes to main/loader:ast_load_resource(), 
> then main/loader:load_resource then main/loader:load_dynamic_module() 
> which then calls the dlopen().
> 
>  
> 
> But again, nowhere along that path do I see anything calling app_mp3’s 
> load_module() function.
> 
> 
> What am I missing?
> 
>  
> 
> Many thanks,
> 
> Matthew
> 

Towards the end of main/loader:load_resource, start_resource() is called. Then, 
near the beginning of that function, you'll see a call to mod->info->load(). 
This function pointer was assigned to app_mp3's load_module function using the 
AST_MODULE_INFO_STANDARD macro at the bottom of app_mp3.c.

Mark Michelson