[avr-gcc-list] Check whether two macros are equal to each other

[Karol Babioch]

Hi,

I'm currently trying to check whether two macros are equal to each 
other. The idea is to generate different code, when they are equal, 
which basically means that they are connected to the same port.

Basically it looks something like this:

#define LED1_DDR DDRD
#define LED2_DDR DDRD
#if LED1_DDR == LED2_DDR
  // Code
#endif

But when trying to compile this, I get the following error:

error: operator '*' has no left operand

Interestingly enough it works just fine, when the values of the macros 
are not some sort of macro itself, but a literal, e.g. "one". It then 
just compiles fine.

Could anyone explain this to me? Is there any way around this (still 
using macros)?

Best regards,
Karol Babioch