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#ifndef WIN32
#ifndef SHM_R
#define SHM_R (256) //共享内存只读
#endif
#ifndef SHM_W
#define SHM_W (128) //共享内存只写
#endif
#ifndef SHM_OPEN
#define SHM_OPEN (SHM_R | SHM_W | SHM_R >> 3 | SHM_W >> 3 | SHM_R >> 6 | SHM_W >> 6) //打开共享内存,如果不存在则出错
#endif
#ifndef SHM_CREATE
#define SHM_CREATE (SHM_OPEN | IPC_CREAT) //建立共享内存,如果已存在则出错
#endif
#include <sys/types.h>
#include <sys/shm.h>
#endif
class yCShm
{
public:
yCShm ()
{
m_nShmID = 0;
}
//析构函数
~yCShm ()
{
}
public:
int Create (const char *pIPCName, int nShmSize)
{
key_t key = ftok (pIPCName, 0x111);
if (key < 0)
{
printf("create shm 1\r\n");
return 0;
}
if ((m_nShmID = shmget (key, nShmSize, SHM_CREATE)) == -1)
{
if ((m_nShmID = shmget (key, nShmSize, SHM_OPEN)) == -1)
{
m_nShmID = 0;
printf("create shm 2\r\n");
return 0;
}
}
printf("create shm 3\r\n");
return 1;
}
int Drop ()
{
if (m_nShmID != 0)
{
shmctl (m_nShmID, IPC_RMID, NULL);
m_nShmID = 0;
}
return 1;
}
void *Shmat ( const void * pAddr=0, int nFlag=0)
{
void *pointer = NULL;
pointer = (void *) shmat (m_nShmID, pAddr, nFlag);
if (pointer == ((void *) -1))
pointer = NULL;
return pointer;
}
private:
int m_nShmID; //共享内存ID
char shm_name[50]; //共享内存映射文件名(也就是Create的第一个参数)
};
int main(int argc, char* argv[])
{
yCShm rshm;
rshm.Create("./temp",1);
rshm.Create("./temp",1024*1024);
void *p=rshm.Shmat(0,0);
if(p)
{
printf("create shm succ\r\n");
}
else
{
printf("create shm fail\r\n");
}
getchar();
rshm.Drop();
return 0;
}