Best way to handle constants

[Maurizio De Santis]

Hello,

I'm writing a wrapper for libgtop2 using ruby-ffi. I would like to read
some constants (mainly version, in order to warn the user about having
installed the right version). I have some doubts:

- FFI::ConstGenerator seems to be not so popular between projects using
ffi. I'm trying to use it and I found that probably its disadvantage is
that you have to specify cppflags in order to make it work; for example on
my machine I have to use it in this way to make it work:

cg = FFI::ConstGenerator.new('libgtop-2.0', cppflags:
'-I/usr/include/libgtop-2.0 -I/usr/include/glib-2.0
-I/usr/lib/x86_64-linux-gnu/glib-2.0/include') do |gen|
gen.include 'glibtop.h'
gen.const(:LIBGTOP_MAJOR_VERSION)
gen.const(:LIBGTOP_MINOR_VERSION)
gen.const(:LIBGTOP_MICRO_VERSION)
end
puts cg.to_ruby

It seems to me that cppflags value is strongly dependent from the
environment (OS and user customizations). Maybe reading LD configurations
could help, but I'm not skilled in C-C++ management, so I'm pretty unsure
about it.

- Are there any other advantages/disadvantages I didn't consider? Do you
have suggestions about how to mitigate these issues, or alternatives to
FFI::ConstGenerator?

Thank you