linux共享記憶體存放字串和數字

參考資料

read me : 在傳輸的時候沒有進行strcpy，而是進行了直接相等，於是沒有能夠將字串賦予正確的值

**1：寫入的是char*，取出的是int

#include #include #include #include #include #include #include #include #include using namespace std;

#define err_exit(m) \
do while (0)
void sem_v(int semid)
;//預設阻塞
int ret = semop(semid, &sops, 1);
if (ret == -1)
}void sem_p(int semid)
;//預設阻塞
int ret = semop(semid, &sops, 1);
if (ret == -1)
}int main()
int shemid = shmget(1234, 1024, 0);//allocates a system v shared memory segment
if (shemid == -1)
int* addr = (int*)shmat(shemid, null, 0);
//從共享記憶體取資料
sem_p(semid);
int p = *addr;
cout << "get value =" << p << endl;
}//寫資料進入到共享記憶體
int semid2 = semget(1235, 0, 0);// get a system v semaphore set identifier
if (semid2 == -1)
int shemid2 = shmget(1235, 1024, 0);//allocates a system v shared memory segment
if (shemid2 == -1)
char* shmptr2 = (char*)shmat(shemid2, null, 0);
//shmptr2 = "nuhao";
strcpy(shmptr2, "nuhao");
sleep(5);
sem_v(semid2);
return 0;
}

#include #include #include #include #include #include #include #include using namespace std;

#define err_exit(m) \
do while (0)
void sem_v(int semid)
;//預設阻塞
int ret = semop(semid, &sops, 1);
if (ret == -1)
}void sem_p(int semid)
;//預設阻塞
int ret = semop(semid, &sops, 1);
if (ret == -1)
}int main()
int shemid = shmget(1235, 1024, 0);//allocates a system v shared memory segment
if (shemid == -1)
char* addr = (char*)shmat(shemid, null, 0);
//從共享記憶體取資料
sem_p(semid);
//char p = *addr;
cout << "get value =" << addr << endl;
}//寫資料傳送給前置伺服器
int semid2 = semget(1234, 0, 0);// get a system v semaphore set identifier
if (semid2 == -1)
int shemid2 = shmget(1234, 1024, 0);//allocates a system v shared memory segment
if (shemid2 == -1)
int* addr2 = (int*)shmat(shemid2, null, 0);
*addr2 = 110;
sleep(5);
sem_v(semid2);
return 0;
}

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