Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> Gilles Chanteperdrix wrote:
>>> [email protected] wrote:
>>>>>> int main( int arc, char *argv[] ) { int i;
>>>>>>
>>>>>> rt_print_auto_init(1);
>>>>>>
>>>>>> rt_printf("--------------- TEST RT-PRINTF  1 ------------\n");
>>>>>>
>>>>>> sleep(1);
>>>>>>
>>>>>> daemon(0,0);
>>>>>>
>>>>>> rt_print_auto_init(1);
>>>> Ok, understood, at least for the scenario where the rt_print feature
>>>> is initialised befor the fork/daemon call. What I don't understand
>>>> is, why it does not work if the rt_print feature is initialised after
>>>> the fork / daemon.
>>> From the way I understand your code, you never tried to initialize the
>>> rt_print feature only after the fork, your code initializes it both
>>> before and after.
>>>
>> There are two initializations: The base init done via __rt_print_init on
>> library loading and the one to be done per-thread via rt_print_init (or
>> on first rt_printf). That printer thread is initialized via the former
>> one. On fork, we do not need to re-run the full __rt_print_init
>> (variables and resources are cloned on fork), we just need to spawn
>> another printer thread.
> 
> Unless I am wrong, rtdk also maintains a list of the thread buffers
> which need to be polled. After the fork, this list will be intact, but
> the threads to which belong the buffers will no longer exist. So, IMO,
> the fork handler should also free all these buffers and reset the list
> to the empty state.

Famous last words: That should work without tweaking. A print_buffer
only contains data references, nothing that points to some uncloned thread.

Jan

-- 
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux

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