互斥锁-多线程
1 #include <stdio.h>
2 #include <unistd.h>
3 #include<signal.h>
4 #include <stdlib.h>
5 #include <pthread.h>
6 #include "../headx.h"
7
8
9 pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; // 静态的初始化锁
10
11 void test_xxx(void)
12 {
13 int num = 0;
14 do {
15 pthread_mutex_lock(&mutex);
16 dbg("线程 %d", num++);
17 pthread_mutex_unlock(&mutex);
18 usleep(1);
19 } while(1);
20 }
21
22 int main(void)
23 {
24 dbg("互斥锁-线程");
25
26 pthread_t thread;
27 if(pthread_create(&thread, NULL, V(test_xxx), NULL)) dbge();
28 do {
29 pthread_mutex_lock(&mutex);
30 sleep(2);
31 pthread_mutex_unlock(&mutex);
32
33 /*
34 * 必须加一个延时
35 * 因为刚释放，刚好CPU时间还没用完，
36 * 又立马加锁了，导致资源一直被当前进程占用
37 */
38 usleep(1);
39 } while(1);
40 }
41
42 // gcc 2.互斥锁.c -pthread
互斥锁-多进程
1 #include <stdio.h>
2 #include <unistd.h>
3 #include<signal.h>
4 #include <stdlib.h>
5 #include <pthread.h>
6 #include "../headx.h"
7
8
9 static void inline *anonymous_mmap_init(void)
10 {
11 void *addr = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
12 if(V(-1) == addr) dbge();
13 return addr;
14 }
15
16 static void inline *process_mutex_init(void)
17 {
18 pthread_mutexattr_t mutex_attr; // 互斥锁属性
19 pthread_mutexattr_init(&mutex_attr); // 初始化互斥锁属性
20
21 // 设置互斥对象为PTHREAD_PROCESS_SHARED共享，即可以在多个进程的线程访问,PTHREAD_PROCESS_PRIVATE为同一进程的线程共享
22 pthread_mutexattr_setpshared(&mutex_attr, PTHREAD_PROCESS_SHARED);
23
24 // 设置同步健壮属性 (https://blog.csdn.net/qq_31442743/article/details/105025450)
25 pthread_mutexattr_setrobust(&mutex_attr, PTHREAD_MUTEX_ROBUST);
26
27 pthread_mutex_t* shm_mutex = anonymous_mmap_init();
28 pthread_mutex_init(shm_mutex, &mutex_attr); // 动态的初始化锁
29
30 return shm_mutex;
31 }
32
33 int main(void)
34 {
35 dbg("互斥锁-进程");
36 pthread_mutex_t* shm_mutex = process_mutex_init();
37
38 int pid;
39 if(-1 == (pid = fork())) dbge();
40 if(!pid) {
41 uint num = 0;
42 do {
43 pthread_mutex_lock(shm_mutex);
44 dbg("子进程 %d", num++);
45 pthread_mutex_unlock(shm_mutex);
46 usleep(1);
47 } while(1);
48 }
49 do {
50 pthread_mutex_lock(shm_mutex);
51 sleep(2);
52 pthread_mutex_unlock(shm_mutex);
53 usleep(1);
54 } while(1);
55 }
56
57
58 // gcc 2.互斥锁.c -pthread
59
60 // https://blog.csdn.net/quantum7/article/details/85049258
