how to use #ifdef with an OR condition?

271

votes

Sorry for asking very basic question. I would like to set OR condition in #ifdef directive.? How to do that ? I tried

#ifdef LINUX | ANDROID
...
..
#endif

It did not work? What is the proper way?

c macros

If you're using | for "or" in your C conditionals too, you're doing it wrong. - Jonathon Reinhart

563

votes

Like this

#if defined(LINUX) || defined(ANDROID)

38

votes

OR condition in #ifdef

#if defined LINUX || defined ANDROID
// your code here
#endif /* LINUX || ANDROID */

or-

#if defined(LINUX) || defined(ANDROID)
// your code here
#endif /* LINUX || ANDROID */

Both above are the same, which one you use simply depends on your taste.

P.S.: #ifdef is simply the short form of #if defined, however, does not support complex condition.

Further-