Re: [avr-gcc-list] simple macro to dig w/ ports

[Peter Harrison]

Jerome Kerdreux wrote:
> Dave Hansen give me a better solution I think, 
> here a cut / paste of his anwser
>
> --- begin included file ---
> #define BIT(p,b)                (b)
>
> #define PORT(p,b)               (PORT ## p)
> #define PIN(p,b)                (PIN ## p)
> #define DDR(p,b)                (DDR ## p)

What does the ## do?

I have tried searching for an answer but the characters are thrown out 
by my desktop and internet search tools

Pete Harrison