我使用posix共享内存构建了一个客户端服务器应用程序,并使用pshared = 1标记了未命名的信号量。信号被放置在共享内存中。该程序运行良好,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。为什么这样?为什么有些posix共享内存段和posix信号对ipcs不可见
/* 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
}
}
我使用ipcs作为创建共享内存/信号量的相同用户。服务器创建共享内存并初始化共享内存中的信号量。我在后台运行服务器,然后在运行客户端之前键入ipcs。 – Anonymous 2009-05-18 22:51:50
仅当客户端完成时,才会删除共享内存和信号量。 – Anonymous 2009-05-18 22:54:45