Linux下共享内存+信号量实现
sem1.c
1 #include"unistd.h"
2 #include"string.h"
3 #include"stdio.h"
4 #include"stdlib.h"
5 #include"linux/types.h"
6 #include"linux/sem.h"
7 #include"linux/ipc.h"
8 #include"linux/shm.h"
9 #include"error.h"
10 int main()
11 {
12 key_t sem_key1=10086,sem_key2=10087,shm_key=10088;
13 int mutexid1,mutexid2;
14 int shmid=0,count=0,*addr,j=0,temp=0;
15 union semun arg1,arg2;
16 struct sembuf P,V;
17 /* define P V Operation*/
18 P.sem_num=0;
19 P.sem_op=-1;
20 P.sem_flg=SEM_UNDO;
21 V.sem_num=0;
22 V.sem_op=1;
23 V.sem_flg=SEM_UNDO;
24 arg1.val=4;
25 arg2.val=0;
26
27
28 mutexid1=semget(sem_key1,1,0666|IPC_CREAT);
29 mutexid2=semget(sem_key2,1,0666|IPC_CREAT);
30 semctl(mutexid1,0,SETVAL,arg1);
31 semctl(mutexid2,0,SETVAL,arg2);
32
33
34 shmid=shmget(shm_key,sizeof(int)*7,IPC_CREAT|0600);
35 addr=(int *)shmat(shmid,NULL,0);//init share memory
36 *(addr)=3;
37 *(addr+1)=3;
38 *(addr+2)=0;
39 shmdt(addr);
40 PRintf(" TIPS: iput\"-1\" to stop input num.\n\n");
41 while(1)
42 {
43
44
45 /**************************************************/
46
47 semop(mutexid1,&P,1);
48
49
50 shmid=shmget(shm_key,sizeof(int)*7,IPC_CREAT|0600);
51 addr=(int *)shmat(shmid,NULL,0);//init share memory
52 j=*(addr+1);
53 count=*(addr+2);
54 if(j==7)j=3;
55
56 printf("Please input data: ");
57 scanf("%d",&temp);
58 printf("\n");
59 *(addr+j)=temp;
60 printf("%d wrrite sucess.\n\n",*(addr+j));
61 if(*(addr+j)==-1)
62 {
63 shmdt(addr);
64 semop(mutexid2,&V,1);
65 return 0;
66 }
67 j++;
68 count++;
69 *(addr+1)=j;
70 *(addr+2)=count;
71 shmdt(addr);
72
73
74 semop(mutexid2,&V,1);
75
76 /**************************************************/
77 }
78 return 0;
79 }
sem2.c
1 #include"unistd.h"
2 #include"stdio.h"
3 #include"stdlib.h"
4 #include"linux/types.h"
5 #include"linux/sem.h"
6 #include"linux/ipc.h"
7 #include"linux/shm.h"
8 #include"error.h"
9 int main()
10 {
11 key_t sem_key1=10086,sem_key2=10087,shm_key=10088;
12 int mutexid1,mutexid2;
13 int shmid=0,count=0,*addr,i=0;
14 union semun arg;
15 struct sembuf P,V;
16 /* define P V operation*/
17 P.sem_num=0;
18 P.sem_op=-1;
19 P.sem_flg=SEM_UNDO;
20 V.sem_num=0;
21 V.sem_op=1;
22 V.sem_flg=SEM_UNDO;
23
24
25 mutexid1=semget(sem_key1,1,0666|IPC_CREAT);
26 mutexid2=semget(sem_key2,1,0666|IPC_CREAT);
27
28
29
30
31
32 while(1)
33 {
34
35
36
37 /***********************************************/
38
39 semop(mutexid2,&P,1);
40
41 shmid=shmget(shm_key,sizeof(int)*7,IPC_CREAT|0600);
42 addr=(int *)shmat(shmid,NULL,0);//init share memory
43 i=*(addr);
44 count=*(addr+2);
45 if(i==7)i=3;
46
47
48 printf("Read data.... ");
49 printf("%d\n",*(addr+i));
50 if(*(addr+i)==-1)
51 {
52 shmdt(addr);
53 shmctl(shmid,IPC_RMID,NULL);
54 semctl(mutexid1,0,IPC_RMID,0);
55 semctl(mutexid2,0,IPC_RMID,0);
56 return 0;
57 }
58 i++;
59 count--;
60 *(addr)=i;
61 *(addr+2)=count;
62 shmdt(addr);
63
64 semop(mutexid1,&V,1);
65 }
66 /***********************************************/
67 return 0;
68 }
在gcc下需要注意Linux和sys两个头文件位置的选择，否则会出现错误。