为什么一些posix共享内存段和posix信号量对ipcs不可见

Question

我使用posix共享内存和posix未命名的信号量和pshared = 1构建了一个客户端服务器应用程序.信号量被放置在共享内存中.程序运行正常,但是当我输入ipcs -m或ipcs -s时,我没有看到我创建的任何共享内存段或信号量.为什么会这样？

/* Server main function for implementing client server program using Posix Shared Memory and Posix Unnamed Semaphores*/  
#include "shm_sem.h"
int main(int argc,char ** argv)  
{  
    int fd;  
    struct shmstruct *ptr;  
    shm_unlink(MYSHM); // delete shared memory segment, if it already exists     
    /* create shared memory, set its size, map it and close descriptor */
    fd=shm_open(MYSHM,O_RDWR|O_CREAT|O_EXCL,0777);  
    ptr=mmap(NULL,sizeof(struct shmstruct),PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);  
    // truncate the size of shared memory to the size of shmstruct  
    ftruncate(fd,sizeof(struct shmstruct)); 
    close(fd);  
    // initialize the semaphores in shared memory  
    sem_init(&ptr->client_mutex,1,1); // set client semaphore to 1  
    sem_init(&ptr->server_mutex,1,0); // set server semaphore to 0  
    for(;;)
        {
        serverPosixShmSem(ptr); // calling server
        }  
}

---

/* Server main function for implementing client server program using Posix Shared Memory and Posix Unnamed Semaphores*/  

#include "shm_sem.h"
int main(int argc,char ** argv)  
{  
    int fd;  
    struct shmstruct *ptr;  
    shm_unlink(MYSHM); // delete shared memory segment, if it already exists     
    /* create shared memory, set its size, map it and close descriptor */
    fd=shm_open(MYSHM,O_RDWR|O_CREAT|O_EXCL,0777);  
    ptr=mmap(NULL,sizeof(struct shmstruct),PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);  
    // truncate the size of shared memory to the size of shmstruct  
    ftruncate(fd,sizeof(struct shmstruct)); 
    close(fd);  

    // initialize the semaphores in shared memory  
    sem_init(&ptr->client_mutex,1,1); // set client semaphore to 1  
    sem_init(&ptr->server_mutex,1,0); // set server semaphore to 0  
    for(;;)
    {
        serverPosixShmSem(ptr); // calling server
    }  
}

Answer 1

ipcs显示System V IPC系统的信息.POSIX信号量和共享内存是一个独立(更好)的系统,不受'ipcs'监控.