[Emc-developers] Halcompile constructable and rtapi_app newinst

[Bertho S. <lc...@va...>]

Hi all,

There is a an option 'constructable' in halcompile that should make it 
possible to instantiate a component from an already loaded module. The 
halcmd instruction 'newinst' would then call down to the module via 
rtapi_app and call the constructor.

However, the option 'constructable' is not documented in halcompile. The 
'newinst' option to halcmd has been commented out with an #if 0 with the 
comment "newinst deferred to version 2.2". The 'newinst' code is present 
in rtapi_app.


The problem is that the constructor signature is missing "const" in its 
arguments and the rtapi_app call down to HAL uses private internal 
functions. Both can be fixed easily and are already prepared to be 
fixed. There are no in-tree components or code using any of this.

However, out-of-tree code could potentially, however unlikely, use it. 
Therefore, changing any of it is a risk, however small it may be.


So, the question is: Does anybody use 'constructable' components and 
direct calls to rtapi_app with 'newinst' to instantiate components from 
the same module?

-- 
Greetings Bertho

(disclaimers are disclaimed)