二十八 线程编程的三个例子

#include <stdio.h>

#include <stdlib.h>

#include <pthread.h>

#define THREAD_NUMBER 3

#define REPEAT_NUMBER 5

#define DELAY_TIME_LEVELS 10.0

void *thrd_func(void *arg)

{

int thrd_num = (int)arg;

int delay_time = 0;

int count = 0;

printf("Thread %d is starting\n", thrd_num);

for (count = 0; count < REPEAT_NUMBER; count++)

{

delay_time = (int)(rand() * DELAY_TIME_LEVELS/(RAND_MAX)) + 1;

sleep(delay_time);

printf("\tThread %d: job %d delay = %d\n",thrd_num, count, delay_time);

}

printf("Thread %d finished\n", thrd_num);

pthread_exit(NULL);
// 退出线程 exit()为退出进程 一个进程包含多个线程

}

int main(void)

{

pthread_t thread[THREAD_NUMBER];
// 创建线程数组。

int no = 0, res;

void * thrd_ret;

srand(time(NULL));
// 初始化随机数

for (no = 0; no < THREAD_NUMBER; no++)

{

res = pthread_create(&thread[no], NULL, thrd_func, (void*)no);
// 创建3个相同的线程

if (res != 0)

{

printf("Create thread %d failed\n", no);

exit(res);

}

}

printf("Create ptread success\nWaitingforthreadstofinish...\n");

for (no = 0; no < THREAD_NUMBER; no+)

{

res = pthread_join(thread[no], &thrd_ret);

if (!res)

{

printf("Thread %d joined\n", no);

}

else

{

printf("Thread %d join failed\n", no);

}

}

return 0;

}

#include <stdio.h>

#include <stdlib.h>

#include <pthread.h>

#define THREAD_NUMBER 3

#define REPEAT_NUMBER 3

#define DELAY_TIME_LEVELS 10.0

pthread_mutex_t mutex;

void *thrd_func(void *arg)

{

int thrd_num = (int)arg;

int delay_time = 0, count = 0;

int res;

res = pthread_mutex_lock(&mutex);
// add lock

if (res)

{

printf("Thread %d lock failed\n", thrd_num);

pthread_exit(NULL);

}

printf("Thread %d is starting\n", thrd_num);

for (count = 0; count < REPEAT_NUMBER; count++)

{

delay_time = (int)(rand() * DELAY_TIME_LEVELS/(RAND_MAX)) + 1;

sleep(delay_time);

printf("\tThread %d: job %d delay = %d\n",

thrd_num, count, delay_time);

}

printf("Thread %d finished\n", thrd_num);

pthread_exit(NULL);

}

int main(void)

{

pthread_t thread[THREAD_NUMBER];

int no = 0, res;

void * thrd_ret;

srand(time(NULL));
// init() rand

pthread_mutex_init(&mutex, NULL);
// xian cheng suo

for (no = 0; no < THREAD_NUMBER; no++)

{

res = pthread_create(&thread[no], NULL, thrd_func, (void*)no); // chuang jian xian cheng

if (res != 0)

{

printf("Create thread %d failed\n", no);

exit(res);

}

}

printf("Createtreadssuccess\nWaitingforthreadstofinish...\n");

for (no = 0; no < THREAD_NUMBER; no++)

{

res = pthread_join(thread[no], &thrd_ret);

if (!res)

{

printf("Thread %d joined\n", no);

}

else

{

printf("Thread %d join failed\n", no);

}

pthread_mutex_unlock(&mutex);

}

pthread_mutex_destroy(&mutex);

return 0;

}

#include <stdio.h>

#include <stdlib.h>

#include <pthread.h>

#include <semaphore.h>

#define THREAD_NUMBER 3

#define REPEAT_NUMBER 3

#define DELAY_TIME_LEVELS 10.0

sem_t sem[THREAD_NUMBER]; // 创建信号量数组，注意是sem_t

void *thrd_func(void *arg)

{

int thrd_num = (int)arg;

int delay_time = 0;

int count = 0;

sem_wait(&sem[thrd_num]);
// 刚开始信号两都为0,所以都不能运行

printf("Thread %d is starting\n", thrd_num);

for (count = 0; count < REPEAT_NUMBER; count++)

{

delay_time = (int)(rand() * DELAY_TIME_LEVELS/(RAND_MAX)) + 1;

sleep(delay_time);

printf("\tThread %d: job %d delay = %d\n",thrd_num, count, delay_time);

}

printf("Thread %d finished\n", thrd_num);

pthread_exit(NULL);

}

int main(void)

{

pthread_t thread[THREAD_NUMBER];

int no = 0, res;

void * thrd_ret;

srand(time(NULL));

for (no = 0; no < THREAD_NUMBER; no++)

{

sem_init(&sem[no], 0, 0);
//每一个信号量的初始值为0

res = pthread_create(&thread[no], NULL, thrd_func, (void*)no);

if (res != 0)

{

printf("Create thread %d failed\n", no);

exit(res);

}

}

printf("Createtreadssuccess\nWaitingforthreadstofinish...\n");

sem_post(&sem[THREAD_NUMBER - 1]);
// 仅为第3个信号量加1

for (no = THREAD_NUMBER - 1; no >= 0; no--)

{

res = pthread_join(thread[no], &thrd_ret);

if (!res)

{

printf("Thread %d joined\n", no);

}

else

{

printf("Thread %d join failed\n", no);

}

sem_post(&sem[(no + THREAD_NUMBER - 1) % THREAD_NUMBER]);// 第3个信号量结束时，为第2个信号量加1

}

for (no = 0; no < THREAD_NUMBER; no++)

{

sem_destroy(&sem[no]);
// 销毁信号量

}

return 0;

}