/*
Criação de threads POSIX em UNIX, com operação join().

Compilar com gcc -Wall thread-join.c -o thread-join -lpthread

Carlos Maziero, DINF/UFPR 2020
*/

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

#define NUM_THREADS 16

void *threadBody (void *id)
{
  long tid = (long) id ;

  printf ("t%02ld: Olá!\n", tid) ;
  sleep (3) ;   
  printf ("t%02ld: Tchau!\n", tid) ;
  pthread_exit (NULL) ;
}

int main (int argc, char *argv[])
{
  pthread_t thread [NUM_THREADS] ;
  pthread_attr_t attr ;   
  long i, status ;

  // para permitir a operação "join" sobre as threads   
  pthread_attr_init (&attr) ;
  pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_JOINABLE) ;

  for (i=0; i<NUM_THREADS; i++)
  {
    printf ("Main: criando thread %02ld\n", i) ;      
    status = pthread_create (&thread[i], &attr, threadBody, (void *) i) ;
    if (status)
    {
      perror ("pthread_create") ;
      exit (1) ;
    }
  }
   
  for (i=0; i<NUM_THREADS; i++)
  {
    printf ("Main: aguardando thread %02ld\n", i);
    status = pthread_join (thread[i], NULL) ;
    if (status)
    {
      perror ("pthread_join") ;
      exit (1) ;
    }
  }
  printf ("Main: fim\n") ;
  pthread_attr_destroy (&attr) ;   
  pthread_exit (NULL) ;
}