Strange blocking behavior with pthreads in DCE when thread executes only a loop.

[Andreas Pantelopoulos]

Hello to all,

During my long journey of porting a novel application on DCE I encountered the following strange behavior.

I managed to reduce the problem to a very simple binary :

#include <iostream>

#include <thread>

#include <cstdlib>

#include <pthread.h>

using namespace std;

#define NUM_THREADS     1       

void *PrintHello(void *threadid) {

   long tid;

   tid = (long)threadid;

   while(1) {

      std::cout << "Hello from thread with id " << tid << std::flush;

   }

   pthread_exit(NULL);

}

int main () {

   pthread_t threads[NUM_THREADS];

   int rc;

   int i;

   cout << "main() : creating thread, " << i << endl;

   rc = pthread_create(&threads[i], NULL, PrintHello, (void *)i);

   if (rc){

     cout << "Error:unable to create thread," << rc << endl;

     exit(-1);

   }

   while(true) {

      std::cout << "Hello from main!\n";

   }

   pthread_exit(NULL);

}

The DCE execution hangs, at the line 347 of pthread-fiber-manager.cc . In this line, a call to pthread_cond_wait (&fiber->thread->condvar, &fiber->thread->mutex) is performed. 

The inline comments say " // and wait until the target thread completes.". However, the thread I create never ends it just loops and prints. 

Is this the expected behavior of the DCE threading management? If yes, isn't that very limited?

Thanks,

Andreas Pantelopoulos