This might be the case of cyclic dependency where header files defining these structures are also including this .h file. -Rajat From: harryxiyou Sent: 30-05-2012 23:08 To: Gaurav Jain Cc: Greg-Kroah-Hartman; Harry Wei; kernelnewbies@xxxxxxxxxxxxxxxxx Subject: Re: [RFC]confusions about 'struct' define On Thu, May 31, 2012 at 1:20 AM, Gaurav Jain <gjainroorkee@xxxxxxxxx> wrote: Hi Gaurav, > Those are forward declarations as they are being used in defining struct > bus_attribute. It's nothing special about GNU-C. That's the case for ANSI-C > too. Pretty standard. > Hmmm.., that is to say, they may be used before definitions in this file or defined in other files like 'struct iommu_ops;' field (Actually, i can not find this field's definition in this file). However, if it has been defined in other header files, we need not declare here, right? -- Thanks Harry Wei _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies