pthread.c

#include <fcntl.h>
#include <pthread.h>
#include <sched.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

static int thread_cnt;

int safe_pthread_create(pthread_t *thread_id, const pthread_attr_t *attr,
                        void *(*thread_fn)(void *), void *arg) {
  int rval;

  rval = pthread_create(thread_id, attr, thread_fn, arg);

  if (rval) {
    printf("failed\n");
    exit(1);
  }

  return rval;
}

int safe_pthread_join(pthread_t thread_id, void **retval) {
  int rval;

  printf("just before pthread join %lx\n", thread_id);
  rval = pthread_join(thread_id, retval);

  if (rval) {
    printf("failed\n");
    exit(1);
  }
  printf("pthread succeed\n");

  return rval;
}

static void spawn_threads(pthread_t *id, void *(*thread_fn)(void *)) {
  intptr_t i;

  for (i = 0; i < thread_cnt; ++i)
    safe_pthread_create(id + i, NULL, thread_fn, (void *)i);
}

static void wait_threads(pthread_t *id) {
  int i;

  while (true) {
    void *x = malloc(0x10);
    free(x);
  }

  for (i = 0; i < thread_cnt; ++i) {
    printf("pthread join never works %d\n", i);
    safe_pthread_join(id[i], NULL);
  }
}

void *thread_fn_01(void *arg) {
  int i;

  printf("%ld stack = %p\n", (intptr_t)arg, &i);

  while (true) {
    void *x = malloc(0x10);
    free(x);
  }
  return NULL;
}

static void test01(void) {
  intptr_t i;
  int k;
  pthread_t id[thread_cnt];
  int res[thread_cnt];
  printf("parent stack %p\n", &k);

  spawn_threads(id, thread_fn_01);
  for (int i = 0; i < thread_cnt; ++i) {
    printf("i=%d pthread_t[i]=%lx\n", i, id[i]);
  }
  wait_threads(id);
  printf("all child returned\n");
}

int main(int argc, char *argv[]) {
  thread_cnt = 1;
  test01();
  return 0;
}