adding preprocessor defines in module makefiles

Mulyadi Santosa mulyadi.santosa at
Thu Sep 8 11:49:19 EDT 2011

Hi :)

On Thu, Sep 8, 2011 at 21:29, Christopher Harvey <chris at> wrote:
> Hi,
> I'm trying to build a kernel module for fun, and I can't figure out a
> clean way to add preprocessor defines that correspond to Kconfig values.
> I'm trying to set CONFIG_SND_DEBUG specifically. My module has only one
> file, and I've tried adding #define CONFIG_SND_DEBUG as the first line
> in the .c file, but now I'm getting the following warning:
> WARNING: "__snd_printk" [/home/chris/snd/snd-foo.ko] undefined!

Without looking at your modules' course, I think that's due to you
were using unexported symbol (in this case, kernel function)


Mulyadi Santosa
Freelance Linux trainer and consultant


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