Multiline C Macro

Question

I am using CPP to expand a test file based on multiple headers. Pre processed file is used by other scripts.

When i use EXPAND_SPEC define. I want the CPP to put following lines in file.

A B
C D
E F

So i tried using following define

#define EXPAND_SPEC\
A B \
C D \
E F

But, CPP replaces this define in following fashion

A B C B E F

How to get new line character using define.

I replaces the define with "A B\nC D\nE F". Doesn't insert actual new line. — user2268152, Jul 17 '14 at 08:21
Generally, newlines (and other separating whitespace characters) are not significant in C source code. Is it in yours? — Jongware, Jul 17 '14 at 08:23
It is not working for me, do i have to add extra option when invoking CPP? — user2268152, Jul 17 '14 at 08:26
You may want toead this, especially the second comment: http://stackoverflow.com/questions/2271078/how-to-make-g-preprocessor-output-a-newline-in-a-macro/2271262#2271262 — Thomas Padron-McCarthy, Jul 17 '14 at 08:28

score 0 · Answer 1 · answered Jul 17 '14 at 08:40

Your request is impossible.

You cannot create new lines with the C/C++ pre-processor.

The only solution is to use a different macro processor or have your macro embed a special character (or string) that can be replaced with a new line using a text manipulation utility like SED or AWK. Both are part of cygwin.

Multiline C Macro

1 Answers1