Nope, these are platform specific. See `/usr/include/ipc.h`:

```c
struct ipc_perm                                                                                                                                                                      
{                                                                                                                                                                                    
  uid_t   uid;    /* [XSI] Owner's user ID */                                                                                                                                        
  gid_t   gid;    /* [XSI] Owner's group ID */                                                                                                                                       
  uid_t   cuid;   /* [XSI] Creator's user ID */                                                                                                                                      
  gid_t   cgid;   /* [XSI] Creator's group ID */                                                                                                                                     
  mode_t    mode;   /* [XSI] Read/write permission */                                                                                                                                
  unsigned short  _seq;   /* Reserved for internal use */                                                                                                                            
  key_t   _key;   /* Reserved for internal use */                                                                                                                                    
};
```