线程相关介绍
一、线程的操作：
demo1.c ------------------join回收整型数int
1 #include
2 #include
3
4 /* int pthread_create(pthread_t *restrict thread,
5 const pthread_attr_t *restrict attr,
6 void *(*start_routine)(void *),
7 void *restrict arg);
8 */
9 void *func1(void *param)
10 {
11 printf("func1 param is %d\n",*((int *)param));
12 static int retval = 100;
13 // pthread_t pthread_self(void);
14 printf("pthread1 ID is %ld\n",pthread_self());
15 // noreturn void pthread_exit(void *retval);
16 pthread_exit((void *)&retval);
17 }
18 int main()
19 {
20 pthread_t thread1;
21 int param = 10;
22 int ret;
23 int *val = NULL;
24 pthread_create(&thread1,NULL,func1,(void *)¶m);
25 if(ret == 0){
26 printf("create thread1 sucess\n");
27 }
28 printf("main thread ID is %ld\n",pthread_self());
29 // int pthread_join(pthread_t thread, void **retval);
30 pthread_join(thread1,(void **)&val);
31 printf("val=%d\n",*val);
32 return 0;
33 }
~ demo1.c ------------------join回收字符串char
1 #include
2 #include
3
4 /* int pthread_create(pthread_t *restrict thread,
5 const pthread_attr_t *restrict attr,
6 void *(*start_routine)(void *),
7 void *restrict arg);
8 */
9 void *func1(void *param)
10 {
11 printf("func1 param is %d\n",*((int *)param));
12 static char *retval = "hello,world!";
13 // pthread_t pthread_self(void);
14 printf("pthread1 ID is %ld\n",pthread_self());
15 // noreturn void pthread_exit(void *retval);
16 pthread_exit((void *)retval);
17 }
18 int main()
19 {
20 pthread_t thread1;
21 int param = 10;
22 int ret;
23 char *val = NULL;
24 pthread_create(&thread1,NULL,func1,(void *)¶m);
25 if(ret == 0){
26 printf("create thread1 sucess\n");
27 }
28 printf("main thread ID is %ld\n",pthread_self());
29 // int pthread_join(pthread_t thread, void **retval);
30 pthread_join(thread1,(void **)&val);
31 printf("val=%s\n",val);
32 return 0;
33 }
线程共享进程的内存空间的代码验证
1 #include
2 #include
3 #include
4
5 /* int pthread_create(pthread_t *restrict thread,
6 const pthread_attr_t *restrict attr,
7 void *(*start_routine)(void *),
8 void *restrict arg);
9 */
10 int p_data = 100;
11 void *func1(void *param)
12 {
13 printf("func1 param is %d\n",*((int *)param));
14 static char *retval = "hello,world!";
15 // pthread_t pthread_self(void);
16 printf("pthread1 ID is %ld\n",pthread_self());
17 // noreturn void pthread_exit(void *retval);
18 while(1){
19 p_data++;
20 printf("func1 p_data = %d\n",p_data);
21 sleep(1);
22 }
23 pthread_exit((void *)retval);
24 }
25 void *func2(void *param)
26 {
27 printf("func2 param is %d\n",*((int *)param));
28 static char *retval2 = "hello,world!";
29 // pthread_t pthread_self(void);
30 printf("pthread2 ID is %ld\n",pthread_self());
31 // noreturn void pthread_exit(void *retval);
32 while(1){
33 p_data++;
34 printf("func2 p_data = %d\n",p_data);
35 sleep(1);
36 }
37 pthread_exit((void *)retval2);
38 }
39 int main()
40 {
41 pthread_t thread1;
42 pthread_t thread2;
43 int param = 10;
44 int ret;
45 char *val = NULL;
46 pthread_create(&thread1,NULL,func1,(void *)¶m);
47 if(ret == 0){
48 printf("create thread1 sucess\n");
49 }
50 pthread_create(&thread2,NULL,func2,(void *)¶m);
51 if(ret == 0){
52 printf("create thread2 sucess\n");
53 }
54 printf("main thread ID is %ld\n",pthread_self());
55 // int pthread_join(pthread_t thread, void **retval);
56 pthread_join(thread1,(void **)&val);
57 pthread_join(thread2,(void **)&val);
58 printf("val=%s\n",val);
59 return 0;
60 }
~
~
~
~ 二、与互斥锁相关的操作：
互斥锁的创建等等
p_data = 5 打印=================================
1 #include
2 #include
3 #include
4 #include
5
6 pthread_mutex_t mutex;
7 int p_data = 0;
8 void *func1(void *param)
9 {
10 pthread_mutex_lock(&mutex);
11 printf("func1 param is %d\n",*((int *)param));
12 static char *retval = "hello,world!";
13 // pthread_t pthread_self(void);
14 printf("pthread1 ID is %ld\n",pthread_self());
15 // noreturn void pthread_exit(void *retval);
16 // int pthread_mutex_lock(pthread_mutex_t *mutex);
17 while(1){
18 p_data++;
19 printf("func1 p_data = %d\n",p_data);
20 sleep(2);
21 if(p_data>5){
22 printf("p_data=5 ==============================\n");
23 pthread_mutex_unlock(&mutex);
24 p_data = 0;
25 sleep(1);
26 }
27 }
28 pthread_exit((void *)retval);
29 }
30 void *func2(void *param)
31 {
32 pthread_mutex_lock(&mutex);
33 printf("func2 param is %d\n",*((int *)param));
34 static char *retval2 = "hello,world!";
35 // pthread_t pthread_self(void);
36 printf("pthread2 ID is %ld\n",pthread_self());
37 // noreturn void pthread_exit(void *retval);
38 while(1){
39 p_data++;
40 printf("func2 p_data = %d\n",p_data);
41 pthread_mutex_unlock(&mutex);
42 sleep(2);
43 }
44 pthread_exit((void *)retval2);
45 }
46 int main()
47 {
48 pthread_t thread1;
49 pthread_t thread2;
50 /* int pthread_mutex_init(pthread_mutex_t *restrict mutex,
51 const pthread_mutexattr_t *restrict attr);
52 */
53 pthread_mutex_init(&mutex,NULL);
54 int param = 10;
55 int ret;
56 char *val = NULL;
57 pthread_create(&thread1,NULL,func1,(void *)¶m);
58 if(ret == 0){
59 printf("create thread1 sucess\n");
60 }
61 pthread_create(&thread2,NULL,func2,(void *)¶m);
62 if(ret == 0){
63 printf("create thread2 sucess\n");
64 }
65 printf("main thread ID is %ld\n",pthread_self());
66 // int pthread_join(pthread_t thread, void **retval);
67 pthread_join(thread1,(void **)&val);
68 pthread_join(thread2,(void **)&val);
69 printf("val=%s\n",val);
70 // int pthread_mutex_destroy(pthread_mutex_t *mutex);
71 pthread_mutex_destroy(&mutex);
72 return 0;
73 }
~
~
~
什么是死锁？
首先要有两把锁，线程1先有锁1后又想拿走锁2，但是锁2被线程2给拿走了。线程2一开始拿了锁2，但又想拿锁1，结果锁1被线程1给拿了，所以双方都卡在那边不动了。中间要有时间片sleep(1),因为线程之间是竞争关系。
三、线程条件控制实现线程的同步
实现p_data = 5时打印==================
1 #include
2 #include
3 #include
4 #include
5
6 pthread_mutex_t mutex;
7 pthread_cond_t cond;
8 int p_data = 0;
9 void *func1(void *param)
10 {
11 printf("func1 param is %d\n",*((int *)param));
12 static char *retval = "hello,world!";
13 printf("pthread1 ID is %ld\n",pthread_self());
14 while(1){
15 pthread_cond_wait(&cond,&mutex);
16
17 printf("func1 p_data = %d\n",p_data);
18 printf("=================================\n");
19 p_data = 0;
20 sleep(1);
21 }
22 pthread_exit((void *)retval);
23 }
24 void *func2(void *param)
25 {
26 pthread_mutex_lock(&mutex);
27 printf("func2 param is %d\n",*((int *)param));
28 static char *retval2 = "hello,world!";
29 // pthread_t pthread_self(void);
30 printf("pthread2 ID is %ld\n",pthread_self());
31 // noreturn void pthread_exit(void *retval);
32 while(1){
33 p_data++;
34 printf("func2 p_data = %d\n",p_data);
35 if(p_data==5){
36 pthread_cond_signal(&cond);
37 }
38 pthread_mutex_unlock(&mutex);
39 sleep(2);
40 }
41 pthread_exit((void *)retval2);
42 }
43 int main()
44 {
45 pthread_t thread1;
46 pthread_t thread2;
47 /* int pthread_mutex_init(pthread_mutex_t *restrict mutex,
48 const pthread_mutexattr_t *restrict attr);
49 */
50 pthread_mutex_init(&mutex,NULL);
51 pthread_cond_init(&cond,NULL);
52 int param = 10;
53 int ret;
54 char *val = NULL;
55 pthread_create(&thread1,NULL,func1,(void *)¶m);
56 if(ret == 0){
57 printf("create thread1 sucess\n");
58 }
59 pthread_create(&thread2,NULL,func2,(void *)¶m);
60 if(ret == 0){
61 printf("create thread2 sucess\n");
62 }
63 printf("main thread ID is %ld\n",pthread_self());
64 // int pthread_join(pthread_t thread, void **retval);
65 pthread_join(thread1,(void **)&val);
66 pthread_join(thread2,(void **)&val);
67 printf("val=%s\n",val);
68 // int pthread_mutex_destroy(pthread_mutex_t *mutex);
69 pthread_mutex_destroy(&mutex);
70 pthread_cond_destroy(&cond);
71 return 0;
72 }
~
~