On Thu, Apr 04, 2024 at 08:03:35PM +0200, Zhu Yanjun wrote: > > > > Because this driver will finally call printk function to output the logs, > > > > the header file include/linux/printk.h needs be included. > > > > > > > > In include/linux/printk.h, pr_fmt is defined. > > > This doesn't make sense, printk.h has: > > > > > > #ifndef pr_fmt > > > #define pr_fmt(fmt) fmt > > > #endif > > > > > > Before or after printk.h should not have an impact. > > > Sorry. The previous mail is not sent successfully. I resend it. > > > #ifndef pr_fmt > > > > ... > > > > #endif > > > > The above will not undefine pr_fmt. > > > > #undef pr_fmt will undefine pr_fmt. > > > > This link explains the above in details. > > > https://www.techonthenet.com/c_language/directives/ifndef.php Why would you want to undefine it? The point is to #define it to the rxe specific value. If it is already set to the rxe specific value before including printk.h then it will work fine? Jason
