嵌入式

linux 信号量实现互斥操作

2019-07-13 09:26发布

站内文章 / 嵌入式Linux
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本次程序实现了通过信号量来实现父进程与子进程互斥操作，当父进程执行打印操作时子进程被阻塞，当子进程执行打印操作时父进程阻塞。实现代码如下:#include #include #include #include #include #include #include #include int semId; int SIZE = 1; union semun { int val; /* Value for SETVAL */ struct semid_ds *buf; /* Buffer for IPC_STAT, IPC_SET */ unsigned short *array; /* Array for GETALL, SETALL */ struct seminfo *__buf; /* Buffer for IPC_INFO (Linux-specific) */ }; void Handle(int s){ if(s == 2){ semctl(semId,0,IPC_RMID); exit(0); } } int main(){ signal(2,Handle); key_t key = ftok(".",4); semId = semget(key,1,IPC_CREAT | IPC_EXCL | 0666); union semun val; val.val = SIZE; if(semctl(semId,0,SETVAL,val) == -1){ printf("semctl error! "); exit(0); } struct sembuf p; p.sem_num = 0; p.sem_op = -1; p.sem_flg = 0; struct sembuf v = {0,1,0}; if(fork() > 0){ while(1){ semop(semId,&p,1); printf("father go go go!!! "); sleep(1); printf("father go go go!!! "); sleep(1); printf("father go go go!!! "); semop(semId,&v,1); } } else{ while(1){ semop(semId,&p,1); printf("child go go go!!! "); sleep(1); printf("child go go go!!! "); sleep(1); printf("child go go go!!! "); semop(semId,&v,1); } } return 0; }实现结果如下: