thread-st.h

/*
 * $Id: thread-st.h$
 * pthread version
 * by Wolfram Gloger 2004
 */

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

pthread_cond_t finish_cond = PTHREAD_COND_INITIALIZER;
pthread_mutex_t finish_mutex = PTHREAD_MUTEX_INITIALIZER;

#ifndef USE_PTHREADS_STACKS
#define USE_PTHREADS_STACKS 0
#endif

#ifndef STACKSIZE
#define STACKSIZE 32768
#endif

struct thread_st {
  char *sp;                           /* stack pointer, can be 0 */
  void (*func)(struct thread_st *st); /* must be set by user */
  pthread_t id;
  int flags;
  struct user_data u;
};

static void thread_init(void) {
  printf("Using posix threads.\n");
  pthread_cond_init(&finish_cond, NULL);
  pthread_mutex_init(&finish_mutex, NULL);
}

static void *thread_wrapper(void *ptr) {
  struct thread_st *st = (struct thread_st *)ptr;

  /*printf("begin %p\n", st->sp);*/
  st->func(st);
  pthread_mutex_lock(&finish_mutex);
  st->flags = 1;
  pthread_mutex_unlock(&finish_mutex);
  pthread_cond_signal(&finish_cond);
  /*printf("end %p\n", st->sp);*/
  return NULL;
}

/* Create a thread. */
static int thread_create(struct thread_st *st) {
  st->flags = 0;
  {
    pthread_attr_t *attr_p = 0;
#if USE_PTHREADS_STACKS
    pthread_attr_t attr;

    pthread_attr_init(&attr);
    if (!st->sp)
      st->sp = malloc(STACKSIZE + 16);
    if (!st->sp)
      return -1;
    if (pthread_attr_setstacksize(&attr, STACKSIZE))
      fprintf(stderr, "error setting stacksize");
    else
      pthread_attr_setstackaddr(&attr, st->sp + STACKSIZE);
    /*printf("create %p\n", st->sp);*/
    attr_p = &attr;
#endif
    return pthread_create(&st->id, attr_p, thread_wrapper, st);
  }
  return 0;
}

/* Wait for one of several subthreads to finish. */
static void wait_for_thread(struct thread_st st[], int n_thr,
                            int (*end_thr)(struct thread_st *)) {
  int i;

  pthread_mutex_lock(&finish_mutex);
  for (;;) {
    int term = 0;
    for (i = 0; i < n_thr; i++)
      if (st[i].flags) {
        /*printf("joining %p\n", st[i].sp);*/
        if (pthread_join(st[i].id, NULL) == 0) {
          st[i].flags = 0;
          if (end_thr)
            end_thr(&st[i]);
        } else
          fprintf(stderr, "can't join\n");
        ++term;
      }
    if (term > 0)
      break;
    pthread_cond_wait(&finish_cond, &finish_mutex);
  }
  pthread_mutex_unlock(&finish_mutex);
}

/*
 * Local variables:
 * tab-width: 4
 * End:
 */