I think Pike's point about "thousands of needless lines of code" is that people do this: #include "foo.h" instead of this: #ifndef __FOO_H__ #include "foo.h

I think Pike's point about "thousands of needless lines of code" is that people do this: #include "foo.h" instead of this: #ifndef __FOO_H__ #include "foo.h" #endif where "foo.h" looks like this: #ifndef __FOO_H__ #define __FOO_H__ /* contents / #endif / __FOO_H__ */ which in the former case results in having to lex foo.h in order to skip the contents. However, as pointed out below, modern compilers will effectively do the same thing for you automatically. [Edited to make the code readable]