Re: [avr-gcc-list] heed help for the C Preprocessor

[Frederik Rouleau]

Try something like this:

#define SDA_PORT C
#define _SDA_DIRECTION(X) DDR##X
#define SDA_DIRECTION(X) _SDA_DIRECTION(X)

The presence of ## prevent the preprocessor to substitute.

Ivan Dimitrov wrote:

> hi all
> when i'm using
> #define SDA_PORT C
> #define SDA_DIRECTION(X) DDR##X
> and in function foo()
> SDA_DIRECTION(SDA_PORT) |= 64;
> so, i am getting 
> DDRSDA_PORT |= 64;
> instead of 
> DDRC |= 64;
>
> how have i write a #def ine to get the right macro? (DDRC |= 64;)
> Regards
> I.
>
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