Question

if in the beginning of my file i do

#define dbg_kprintf \
   if (x_var) kprintf

I late on do statements using

dbg_kprintf ("blablabla");

My question is that will dbg_kprintf be only defined if xvar is defined somewhere else? If it is not then will dbg_kprintf statements not be used at compile time?

Thanks.

Answer 1

No, in that example, x_var has to exist somewhere or it will fail to compile. You are looking for something like

#if (x_var)
  #define dbg_kprintf kprintf
#else
  #define dbg_kprintf
#endif