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/* 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

}

void

do_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. */

}

int

main()

{

   do_pass ();

   return 0;  /* Set breakpoint here before exit. */

}

/* EndSourceFile */