/* BeginSourceFile tls.c  This file creates and deletes threads. It uses thread local storage  variables too. */#include <unistd.h>#include <stdlib.h>#include <stdio.h>#include <assert.h>#include <pthread.h>#include <semaphore.h>#include <errno.h>#define N_THREADS 3/* Uncomment to turn on debugging output *//*#define START_DEBUG*//* Thread-local storage.  */__thread int a_thread_local;__thread int another_thread_local;/* Global variable just for info addr in gdb.  */int a_global;/* Print the results of thread-local storage.  */int thread_local_val[ N_THREADS ];int another_thread_local_val[ N_THREADS ];/* Semaphores to make sure the threads are alive when we print the TLS   variables from gdb.  */sem_t tell_main, tell_thread;void print_error (){  switch (errno)  {    case EAGAIN:      fprintf (stderr, "EAGAIN\n");      break;    case EINTR:      fprintf (stderr, "EINTR\n");      break;    case EINVAL:      fprintf (stderr, "EINVAL\n");      break;    case ENOSYS:      fprintf (stderr, "ENOSYS\n");      break;    case ENOENT:      fprintf (stderr, "ENOENT\n");      break;    case EDEADLK:      fprintf (stderr, "EDEADLK\n");      break;    default:      fprintf (stderr, "Unknown error\n");      break;   } }/* Routine for each thread to run, does nothing.  */void *spin( vp )    void * vp;{    int me = (long) vp;    int i;        /* Use a_global. */    a_global++;    a_thread_local = 0;    another_thread_local = me;    for( i = 0; i <= me; i++ ) {        a_thread_local += i;    }    another_thread_local_val[me] = another_thread_local;    thread_local_val[ me ] = a_thread_local; /* here we know tls value */    if (sem_post (&tell_main) == -1)     {        fprintf (stderr, "th %d post on sem tell_main failed\n", me);        print_error ();        return;     }#ifdef START_DEBUG    fprintf (stderr, "th %d post on tell main\n", me);#endif    while (1)      {#ifdef START_DEBUG        fprintf (stderr, "th %d start wait on tell_thread\n", me);#endif        if (sem_wait (&tell_thread) == 0)          break;        if (errno == EINTR)          {#ifdef START_DEBUG            fprintf (stderr, "th %d wait tell_thread got EINTR, rewaiting\n", me);#endif            continue;          }        else          {              fprintf (stderr, "th %d wait on sem tell_thread failed\n", me);            print_error ();            return;         }      }#ifdef START_DEBUG      fprintf (stderr, "th %d Wait on tell_thread\n", me);#endif}voiddo_pass(){    int i;    pthread_t t[ N_THREADS ];    int err;    for( i = 0; i < N_THREADS; i++)    {        thread_local_val[i] = 0;        another_thread_local_val[i] = 0;    }       if (sem_init (&tell_main, 0, 0) == -1)    {      fprintf (stderr, "tell_main semaphore init failed\n");      return;    }    if (sem_init (&tell_thread, 0, 0) == -1)    {      fprintf (stderr, "tell_thread semaphore init failed\n");      return;    }    /* Start N_THREADS threads, then join them so that they are terminated.  */    for( i = 0; i < N_THREADS; i++ )     {        err = pthread_create( &t[i], NULL, spin, (void *) (long) i );        if( err != 0 ) {            fprintf(stderr, "Error in thread %d create\n", i );        }     }    for( i = 0; i < N_THREADS; i++ )      {        while (1)          {#ifdef START_DEBUG            fprintf (stderr, "main %d start wait on tell_main\n", i);#endif            if (sem_wait (&tell_main) == 0)              break;            if (errno == EINTR)              {#ifdef START_DEBUG                fprintf (stderr, "main %d wait tell_main got EINTR, rewaiting\n", i);#endif                continue;              }            else              {                fprintf (stderr, "main %d wait on sem tell_main failed\n", i);                print_error ();                return;              }            }       }#ifdef START_DEBUG    fprintf (stderr, "main done waiting on tell_main\n");#endif    i = 10;  /* Here all threads should be still alive. */    for( i = 0; i < N_THREADS; i++ )     {       if (sem_post (&tell_thread) == -1)        {           fprintf (stderr, "main %d post on sem tell_thread failed\n", i);           print_error ();           return;        }#ifdef START_DEBUG      fprintf (stderr, "main %d post on tell_thread\n", i);#endif     }    for( i = 0; i < N_THREADS; i++ )     {        err = pthread_join(t[i], NULL );        if( err != 0 )         {            fprintf (stderr, "error in thread %d join\n", i );         }    }    i = 10;  /* Null line for setting bpts on. */   }intmain(){   do_pass ();   return 0;  /* Set breakpoint here before exit. */}/* EndSourceFile */