Using 'defined' with 'ifdef'?

Question

consider the snippet below:

#ifdef AAA && (defined BBB)
...
#endif

gcc-4.5.2 complains on this line:

extra tokens at the end of #ifdef directive.

Is it illegal to combine ifdef and defined ?

Thanks!

Answer 1

The #ifdef requires a single identifier and is equivalent to #if defined(identifier).

You need to use the #if directive if you have a more complex expression:

#if (defined AAA) && (defined BBB) // true if AAA and BBB are both defined
#if AAA && (defined BBB)           // true if AAA is true and BBB is defined

Answer 2

#ifdef will only work on one token. If you want to use more than one then write

#if defined(AAA) && defined(BBB)