Why autoconf preset output variables for directories are written in small letters?

Question

When I read the manual for autoconf, I noticed variables for directories, like 'srcdir', are written in small letters, while other variables are written in large letters.

Why does autoconf do so? And should I keep this naming rule when I write Makefile?

Answer 1

I don't know the original reason why Automake and Autoconf do this, but probably because some people were using this convention in their Makefiles before Automake was written.

If you use Automake, then you have to follow this convention. A somethingdir variable has a special meaning, it tells Automake where to install files listed in 'primaries' like something_DATA.

If you write your own Makefile, it's probably a good idea to keep this naming convention, since many people will be familiar with it.