linux下的C\C++多进程多线程编程

1、多进程编程

 #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;
 }

 

2、多线程编程

 #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;
 }

 3、线程同步与互斥

1）、互斥

 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);

 

2）、条件变量

 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);
 }