Found in an old programming assignment for 9th grade Intro to Computer Programming class:
#ifndef NULL #define NULL NULL #endif
Now, I’m hoping that I wrote that just to fuck with the teacher (which I did a LOT because she was mean and didn’t know jack about C, C++, or any language except MS-QBasic).
BTW, I confirmed that the GNU C/C++ preprocessor simply ignores those three lines. I’m hoping any other sane preprocessor does, too.