#include <pthread.h>
#include <stdio.h>

pthread_mutex_t mtx;
pthread_cond_t cond;
unsigned long x,y;

void * task(void *data)
{
 (void)data;
 pthread_mutex_lock(&mtx);
 while(x<=y)
 {
  fprintf(stderr,"until now %lu <= %lu\n",x,y);
  pthread_cond_wait(&cond,&mtx);
 }
 pthread_mutex_unlock(&mtx);

 fprintf(stderr,"and then %lu > %lu\n",x,y);
 return((void *)0);
}

int main(void)
{
 pthread_t th;
 void * result;
 unsigned long t;

 x=0; y=10000000;

 pthread_mutex_init(&mtx,(pthread_mutexattr_t *)0);
 pthread_cond_init(&cond,(pthread_condattr_t *)0);

 if(pthread_create(&th,(pthread_attr_t *)0,task,(void *)0))
  { fprintf(stderr,"Pb create\n"); return(1); }

 for(t=0;t<20000000;t++)
 {
  if(!(t%100000)) fputc('.',stderr);
  pthread_mutex_lock(&mtx);
  if((x=t)>y) pthread_cond_broadcast(&cond);
  pthread_mutex_unlock(&mtx);
 }

 fputc('\n',stderr);

 if(pthread_join(th,&result))
  { fprintf(stderr,"Pb join\n"); return(1); }
 if(pthread_cond_destroy(&cond))
  { fprintf(stderr,"Pb condition destroy\n"); return(1); }
 if(pthread_mutex_destroy(&mtx))
  { fprintf(stderr,"Pb mutex destroy\n"); return(1); }

  return(0);
}