Hi Dirk,
Pointers should be passed the other way around: from RT-threads to the
Linux task. As it is, ptr_b points to a virtual address in some random
user-space task that happened to be current. One way to solve this
problem is to allocate a block of memory in your RT-module, then pass
a pointer (e.g., via an RT-FIFO) to your Linux task, and allocate
the object in this area by redefining operator::new.
Michael.
Dirk Pohl [EIT] ([EMAIL PROTECTED]) wrote:
> Hello,
> I created an object in my linux-application. Now I want to call
> memberfunctions of this object from RT-Threads. I included the files from
> the examples/cpp directory, defined a pointer on the object an did this
> __do_global_ctors thing. From the linux application I start the
> RT-Thread like in the examples/frank example and hand the pointer to
> the object down through a FIFO. The RT-Thread then calls
> the function (ptr_b -> calculate()), incrementing the object variable.
> Meanwhile, my application just counts to 10^9 doing nothing else, and I
> can watch the thread counting (it sends the actual value to console).
> THIS ALL WORKS FINE!
> Now I tried to also print the actual value in my linux-application, while
> the thread runs. AND THEN: the thread suddenly stops running (at
> different points: once it counts to 7, to 15, to 8 ...). The variable
> is not incremented any more.
>
> Here are some cutouts (which I hope are important ...) from my programs:
> [CObjekt.cpp]
> CObjekt::CObjekt() { a=1; b=1; }
> CObjekt::~CObjekt() {}
> void CObjekt::calculate(void) { a += b; }
> int CObjekt::show(void) { return a; }
>
> [rt_app.cpp] RTLinux module
>
> CObjekt* ptr_b;
> pthread_t thread;
>
> void * huelle (void* arg) {
> struct sched_param p;
> int a;
>
> p.sched_priority = 1;
> pthread_setschedparam (pthread_self(), SCHED_FIFO, &p);
> while (1) {
> pthread_wait_np ();
> ptr_b -> calculate();
> a = ptr_b -> show();
> rtl_printf("Result: %d\n", a);
> }
> return 0;
> }
>
> int command_handler(unsigned int fifo) {
> struct my_msg_struct msg;
> int err;
>
> while ((err = rtf_get(1, &msg, sizeof(msg))) == sizeof(msg)) {
> switch (msg.command) {
> case START_TASK:
> ptr_b = msg.data;
> pthread_make_periodic_np(thread, gethrtime(),100000000);
> break;
> case STOP_TASK:
> pthread_suspend_np(thread);
> break;
> }
> }
> return 0;
> }
> [init_module omitted]
> [cleanup omitted]
>
> main_app.cpp //linux application
> int main(void) {
> CObjekt * ptr_a = new CObjekt; // Objekt instanciated
> int fd0;
> struct my_msg_struct msg;
> int i;
>
> if ((fd0 = open("/dev/rtf1", O_WRONLY)) < 0 ) {
> exit(1);
> }
> msg.command = START_TASK;
> msg.data = ptr_a;
> if (write(fd0, &msg, sizeof(msg)) < 0) {
> }
> for (i=0; i<=1000000000; i++) { // if I leave this block empty
> if ( (i%1000000) == 0) { // all is ok
> cout << ptr_a -> show() << "\n"; // if I access the variable
> } // thread hangs up
> }
> msg.command = STOP_TASK;
> if (write(fd0, &msg, sizeof(msg)) < 0) {
> }
> fprintf(stdout,"Value: %d\n", ptr_a->show());
> delete ptr_a;
> return close(fd0);
> }
>
> I'd appreciate any help, comments, etc. since I'm new to all of this.
> ---
> Dirk Pohl
> University of Kaiserslautern
>
>
>
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