linux多线程示例

 1 #include <stdio.h>

 2 #include <unistd.h>

 3 #include <stdlib.h>

 4 #include <pthread.h>

 5 

 6 typedef void* (*fun)(void*);

 7 

 8 fun fun1, fun2;

 9 

10 pthread_mutex_t pmu = PTHREAD_MUTEX_INITIALIZER;

11 pthread_cond_t cond;

12 pthread_t pid1, pid2;

13 int flag = 0;

14 int gnum = 0;

15 int gsub = 100;

16 

17 void *  func1(void * para)

18 {

19     int k = (int)para;

20     printf("func1, ******\n");

21     while(gnum<=100)

22     {   

23         pthread_mutex_lock(&pmu);

24         printf("gnum == %d", gnum);

25         while(gnum==50)

26         {   

27             printf("suspend thread1 at gnum==50 !!! \n");

28             pthread_cond_wait(&cond, &pmu);

29             gnum++;

30        }

31         ++gnum;

32         ++flag;

33         ++k;

34         //printf("flag = %d, k = %d\n", flag, k);

35         pthread_mutex_unlock(&pmu);

36         printf("I am func1\n");

37     }

38             pthread_exit((void*)0);

39 

40 }

41 

42 void * func2(void * para)

43 {

44     int f = (int)para;

45     printf("f == %d\n", f);

46     printf("pthread2 start running !\n");

47     void * ret = NULL;

48     while(gsub>=0)

49     {

50         pthread_mutex_lock(&pmu);

51         gsub--;

52         printf("gsub= %d ", gsub);

53         if(gsub == 20)

54         {

55             printf("now gsnb ==20, and send signal\n");

56             pthread_cond_signal(&cond);

57         }

58         ++flag;

59        ++f;

60         printf("flag = %d, f = %d\n", flag, f);

61         pthread_mutex_unlock(&pmu);

62         printf("I am func2 \n");

63     }

64     //pthread_join(pid1, &ret);

65     pthread_exit((void*)0);

66 }

67 

68 int main()

69 {

70     int id = 0;

71     void * ret = NULL;

72     int key = 5;

73 

74     pthread_cond_init(&cond, NULL);  //属性设置NULL默认属性

75     id = pthread_create(&pid1, NULL, func1, (void*)key);

76     if(id != 0)

77     {

78         printf("pthread_create error !\n");

79         exit(0);

80     }

81 

82     if(pthread_create(&pid2, NULL, func2, (void*)key))

83     {

84         printf("pthread_create error ! \n");

85         exit(0);

86     }

87  pthread_join(pid2, &ret);　　　　　　//等待pid2线程退出 88 pthread_join(pid1, &ret);　　　　　　//等待pid1线程退出

　　　　//pthread_detach(pid1);　　　　　　　　//主线程与pid1线程进行分离，一般用来实现异步返回
　　　　//pthread_detach(pid2);　　　　　　　　//同上 89     pthread_exit((void*)0);

90 }

gcc test_thread.c -lpthread
./a.out

线程池实例代码：

  1 #include <stdio.h>

  2 #include <stdlib.h>

  3 #include <unistd.h>

  4 #include <sys/types.h>

  5 #include <pthread.h>

  6 #include <assert.h>

  7 

  8 typedef struct worker

  9 {

 10     //回调函数，任务运行时会调用此函数，也可以声明为其他形式；

 11     void * (*process)(void *arg);   //该函数返回值是任意类型的；参数也是任意类型的；`

 12     void *arg;  //回调函数的参数；

 13     struct worker *next;

 14 }CThread_worker;

 15 

 16 //线程池结构

 17 typedef struct

 18 {

 19     pthread_mutex_t queue_lock;     //互斥量

 20     pthread_cond_t queue_ready;     //条件变量

 21 

 22     //链表结构， 线程池中所有等待任务

 23     CThread_worker *queue_head;

 24     

 25     //是否销毁线程池

 26     int shutdown;

 27     pthread_t *threadid;

 28     

 29     //线程池中允许的活动线程数目；

 30     //线程池中允许的活动线程数目；

 31     int max_thread_num;

 32     //当前等待队列的任务数目;

 33     int  cur_queue_size;

 34 

 35 }CThread_pool;

 36 

 37 int pool_add_worker(void * (*process)(void *arg), void *arg);

 38 void * thread_routine(void *arg);

 39 

 40 static CThread_pool *pool = NULL;

 41 void pool_init(int max_thread_num)

 42 {

 43     pool = (CThread_pool*)malloc(sizeof(CThread_pool));

 44 

 45 //初始化互斥量；

 46     pthread_mutex_init(&(pool->queue_lock), NULL);

 47 //初始化条件变量

 48     pthread_cond_init(&(pool->queue_ready), NULL);

 49 

 50     pool->queue_head = NULL;

 51     

 52 //最大线程数目

 53     pool->max_thread_num = max_thread_num;

 54 //当前线程数目

 55     pool->cur_queue_size = 0;

 56     

 57     pool->shutdown = 0;

 58     pool->threadid = (pthread_t*)malloc(max_thread_num * sizeof(pthread_t));

 59     int i = 0;

 60     for(i=0; i<max_thread_num;i++)

 61     {

 62         pthread_create(&(pool->threadid[i]), NULL, thread_routine, NULL);

 63     }

 64 }

 65 

 66 //向线程池中加入任务

 67 int pool_add_worker(void*(*process)(void *arg), void *arg)

 68 {

 69     //构建一个新任务

 70     CThread_worker *newworker = (CThread_worker *)malloc(sizeof(CThread_worker));

 71     newworker->process = process;

 72     newworker->arg = arg;

 73     //别忘了置空

 74     newworker->next = NULL;

 75 

 76 //加锁互斥量

 77     pthread_mutex_lock(&(pool->queue_lock));

 78     //将任务加入到等待队列中

 79     CThread_worker *member = pool->queue_head;

 80     if(member !=NULL)

 81     {

 82         while(member->next != NULL)

 83             member = member->next;

 84         member->next = newworker;

 85     }

 86     else

 87     {

 88         pool->queue_head = newworker;

 89     }

 90     

 91     assert(pool->queue_head != NULL);

 92     pool->cur_queue_size++;

 93     pthread_mutex_unlock(&(pool->queue_lock));

 94     

 95     //好了，等待队列中有任务了，唤醒一个等待线程；

 96     //     注意如果所有线程都在忙碌，这句没有任何作用

 97     pthread_cond_signal(&(pool->queue_ready));

 98     return 0;

 99 }

100 

101 /*销毁线程池，等待队列中的任务不会再被执行，

102 *但是正在运行的线程会一直 把任务运行完后 再退出；

103 */

104 

105 int pool_destroy()

106 {

107     if(pool->shutdown)

108         return -1;   //防止两次调用

109     pool->shutdown = 1;

110     

111     //唤醒所有等待线程，线程池要销毁了 

112     pthread_cond_broadcast(&(pool->queue_ready));

113     

114     //阻塞等待线程退出， 否则就成僵尸了

115     int i;

116     for(i=0; i<pool->max_thread_num; i++)

117     {

118         pthread_join(pool->threadid[i], NULL);

119     }

120 

121     free(pool->threadid);

122 

123     //销毁等待队列

124     CThread_worker *head = NULL;

125     while(pool->queue_head != NULL)

126     {

127         head=pool->queue_head;

128         pool->queue_head = pool->queue_head->next;

129         free(head);

130     }

131 

132     //条件变量和互斥量也别忘了销毁

133     pthread_mutex_destroy(&(pool->queue_lock));

134     pthread_cond_destroy(&(pool->queue_ready));

135 

136     free(pool);

137      /*销毁后指针置空是个好习惯*/

138     pool = NULL;

139     return 0;

140 }

141 

142 void* thread_routine(void *arg)

143 {

144                    printf("start thread 0x%x\n", pthread_self());

145     while(1)

146     {

147         pthread_mutex_lock(&(pool->queue_lock));

148 /*如果等待队列为0并且不销毁线程池，则处于阻塞状态; 注意

149  *pthread_cond_wait是一个原子操作，等待前会解锁，唤醒后会加锁*/

150         while(pool->cur_queue_size == 0 && !pool->shutdown)

151         {

152             printf("thread 0x%x is waiting \n", pthread_self());

153             pthread_cond_wait(&(pool->queue_ready), &(pool->queue_lock));

154         }

155 

156         //线程池要销毁了；

157         if(pool->shutdown)

158         {

159             //遇到break,continue,return等跳转语句，千万不要忘记先解锁*/

160             pthread_mutex_unlock(&(pool->queue_lock));

161             printf("thread 0x %x will exit \n", pthread_self());

162             pthread_exit(NULL);

163         }

164 

165         printf("thread 0x %x is starting to work \n", pthread_self());

166 

167         //使用断言

168         assert(pool->cur_queue_size!= 0);

169         assert(pool->queue_head!= NULL);

170 

171         //等待队列长度减去1，并取出链表中的头元素

172         pool->cur_queue_size--;

173        CThread_worker *worker = pool->queue_head;

174         pool->queue_head = worker->next;

175         pthread_mutex_unlock(&(pool->queue_lock));

176 

177         //调用回调函数，执行任务

178         (*(worker->process))(worker->arg);

179         free(worker);

180         worker = NULL;

181     }

182     //这一句正常情况下是不可达的

183     pthread_exit(NULL);

184 }

185 

186 //test code

187 void *myprocess(void *arg)

188 {

189     printf("threadid is 0x%x, working on task %d\n", pthread_self(), *(int*)arg);

190     sleep(1);  //休息一秒，延长任务的执行时间

191     return NULL;

192 }

193 

194 int main(int argc, char** argv)

195 {

196     pool_init(3); /*线程池中最多三个活动线程*/

197 

198     //连续向线程池中放入10个任务；

199     int *workingnum = (int*)malloc(sizeof(int)*10);

200     int i;

201     for(i=0; i< 10;i++)

202     {

203         workingnum[i] = i;

204         pool_add_worker(myprocess, &workingnum[i]);

205     }

206 

207     sleep(5);

208 //销毁线程池；  

209     pool_destroy();

210     free(workingnum);

211 

212     return 0;

213 }