共享内存 中 存结构体，多线程多进程间实现共享。

#define FILE_MSG_KEY	0xc54be5 ///< File message key.
#define PROC_MEM_SIZE 4096*3
#define MAX_SHARE_PROC	9
#define IPC_CREAT  00001000   /* create if key is nonexistent */
static int mFileId,qFileId;
static void *pShareMem;
int pShareMemInit(int key)
{
	int mid = shmget(key, PROC_MEM_SIZE * MAX_SHARE_PROC, IPC_CREAT | 0660);
	printf("shared memory size %d\n", PROC_MEM_SIZE * MAX_SHARE_PROC);
	if(mid < 0)
		mid = shmget(key, 0, 0);
	printf("shared memory id:%d\n",mid);
	if(mid < 0)
		return -1;
	return mid;
}

int readSysInfoCfg()
{
	mFileId = pShareMemInit(FILE_MSG_KEY);
	if(mFileId < 0)
		return -1;
	pShareMem = shmat(mFileId,0,0);

 	SysInfo *pSysInfo = (SysInfo *)pShareMem;

}

共享内存，多进程间共享结构体