#include <stdlib.h> 
#include <sys/types.h> 
#include <unistd.h> 
 
int main() 
{ 
  pid_t child_pid; 
 
  /* 创建一个子进程 */ 
  child_pid = fork(); 
  if(child_pid == 0) 
  { 
    printf("child pid\n"); 
    exit(0); 
  } 
  else 
  { 
    printf("father pid\n"); 
    sleep(60); 
  } 
   
  return 0; 
} 

#include <stdio.h> 
#include <pthread.h> 
 
struct char_print_params 
{ 
  char character; 
  int count; 
}; 
 
void *char_print(void *parameters) 
{ 
  struct char_print_params *p = (struct char_print_params *)parameters; 
  int i; 
 
  for(i = 0; i < p->count; i++) 
  { 
    fputc(p->character,stderr); 
  } 
 
  return NULL; 
} 
 
int main() 
{ 
  pthread_t thread1_id; 
  pthread_t thread2_id; 
  struct char_print_params thread1_args; 
  struct char_print_params thread2_args; 
 
  thread1_args.character = 'x'; 
  thread1_args.count = 3000; 
  pthread_create(&thread1_id, NULL, &char_print, &thread1_args); 
 
  thread2_args.character = 'o'; 
  thread2_args.count = 2000; 
  pthread_create(&thread2_id, NULL, &char_print, &thread2_args); 
 
  pthread_join(thread1_id, NULL); 
  pthread_join(thread2_id, NULL); 
 
  return 0; 
} 

pthread_mutex_t mutex; 
pthread_mutex_init(&mutex, NULL); 
 
/*也可以用下面的方式初始化*/ 
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; 
 
pthread_mutex_lock(&mutex); 
/* 互斥  */ 
 
thread_flag = value; 
 
pthread_mutex_unlock(&mutex); 

int thread_flag = 0; 
pthread_mutex_t mutex; 
pthread_cond_t thread_flag_cv;\ 
 
void init_flag() 
{ 
  pthread_mutex_init(&mutex, NULL); 
  pthread_cond_init(&thread_flag_cv, NULL); 
  thread_flag = 0; 
} 
 
void *thread_function(void *thread_flag) 
{ 
  while(1) 
  { 
    pthread_mutex_lock(&mutex); 
    while(thread_flag != 0 ) 
    { 
      pthread_cond_wait(&thread_flag_cv, &mutex); 
    } 
    pthread_mutex_unlock(&mutex); 
 
    do_work(); 
  } 
 
  return NULL; 
} 
 
void set_thread_flag(int flag_value) 
{ 
  pthread_mutex_lock(&mutex); 
  thread_flag = flag_value; 
 
  pthread_cond_signal(&thread_flag_cv); 
  pthread_mutex_unlock(&mutex); 
}