I've believed I've used the following construct before in other compilers without warning. Shouldn't this be valid in the Arduino 1.6.9 preprocessor?
#ifdef OPTION1 || OPTION2
// stuff here
The above throws the following warning:
"warning: extra tokens at end of #ifdef directive"
#if defined(OPTION1) || defined(OPTION2)
thanks thomai for the information. Did the simple || ever work in older compilers?
I seem to remember in the dim past being able to use just the #ifdef with the ||.
if OPTION1 and OPTION2 are expressions that the preprocessor can evaluate to true or false, then you could write:
#if OPTION1 || OPTION2