共享存储

两个进程之间通过共享存储传递结构体数据，进程之间通过信号量来同步操作

shmsev.c

#include <sys/shm.h>#include <sys/ipc.h>#include <sys/sem.h>#include <stdio.h>#include <stdlib.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <errno.h>#define SHM_SIZE 1024union semum{int val;struct semid_ds *buf;unsigned short *array;};typedef struct{int age;char name[10];}people;int main(){key_t key;int shmid,semid;union semum sem_val;struct sembuf sem_buf;char buf[1024];char temp[10];people *p;int i=0;key = ftok("/root/one", 2013);shmid = shmget(key, SHM_SIZE, IPC_CREAT|0666);semid = semget(key, 1, IPC_CREAT|0666);printf("key = %d\n", key);printf("shmid = %d\n", shmid);printf("semid = %d\n", semid);sem_val.val = 1;semctl(semid, 0, SETVAL, sem_val);p = (people *)shmat(shmid, 0, 0);//P()sem_buf.sem_num = 0;sem_buf.sem_op = -1;sem_buf.sem_flg = SEM_UNDO;semop(semid, &sem_buf, 1);memset(temp, 0x00, sizeof(temp));strcpy(temp, "wang");temp[4] = '0';for(i=0; i<3; i++){temp[4]+=1;strncpy((p+i)->name, temp, 5);(p+i)->age=20+i;}//strcpy(buf, "Can you hear me? I am servers!\n");//memcpy(shm_addr, buf, strlen(buf));//V()sem_buf.sem_op = 1;semop(semid, &sem_buf, 1);shmdt(p);return 0;}

shmcli.c

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <errno.h>#include <sys/sem.h>#include <sys/ipc.h>#include <sys/shm.h>#define SHM_SIZE 1024typedef struct{int age;char name[10];}people;int main(){key_t key;int shmid, semid;struct sembuf sem_buf;people *p;int i=0;key = ftok("/root/one", 2013);shmid = shmget(key, 0, 0666);semid = semget(key, 1, 0666);printf("key = %d\n", key);printf("shmid = %d\n", shmid);printf("semid = %d\n", semid);p = (people *)shmat(shmid, 0, 0);//P()sem_buf.sem_num = 0;sem_buf.sem_op = -1;sem_buf.sem_flg = SEM_UNDO;semop(semid, &sem_buf, 1);for(i=0; i<3; i++){printf("name:%s\n",(*(p+i)).name);printf("age %d\n", (*(p+i)).age);}//printf("cli recved==>: %s \n", shm_addr);//V()sem_buf.sem_op = 1;semop(semid, &sem_buf, 1);shmdt(p);//semctl(semid, 0, IPC_RMID, 0);//shmctl(shmid, IPC_RMID, NULL);return 0;}

[root@localhost one]# ./shmsev
key = -586474867
shmid = 1245204
semid = 524291
[root@localhost one]# ./shmcli
key = -586474867
shmid = 1245204
semid = 524291
name:wang1
age 20
name:wang2
age 21
name:wang3
age 22