From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4ACDBBF8.6090007@domain.hid> Date: Thu, 08 Oct 2009 12:16:24 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <0000ACAE.4ACDAF68@domain.hid> <4ACDA23D.4000507@domain.hid> <4ACDB034.7060801@domain.hid> <4ACDB1F8.6060305@domain.hid> In-Reply-To: <4ACDB1F8.6060305@domain.hid> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] Re : rt_printf with daemonized task List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gilles Chanteperdrix Cc: "xenomai@xenomai.org" , "oliver.schlenker@domain.hid" Gilles Chanteperdrix wrote: > Jan Kiszka wrote: >> Gilles Chanteperdrix wrote: >>> oliver.schlenker@domain.hid 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