How to #include a single line in C

Question

Apperantly rumor has it that it is possible to #include a single line in C (possibly with gcc)

e.g.

#include <file.h> 5

To get like line 5. Cannot find anything like that in the cpp docs.

Or which preprocessors allow doing ugly hacks like that?!

Answer 1

I've never heard of such a feature, and I have certainly not come across any preprocessors that would support it.

In any case, it sounds like a really bad idea. What if someone inserted a blank line at the top of file.h... would you be happy for that change to break your program?

If you control file.h, I think the best approach is to extract line 5 into a separate header, and #include it both into file.h and into your main program.

Answer 2

I don't think that's possible with GCC or any other compiler for that matter.