Feature #15156


Have a 'c_headers' specifier in Gem::Specification.

Added by v0dro (Sameer Deshmukh) over 2 years ago. Updated over 2 years ago.

Third Party's Issue
Target version:


Currently if one Ruby gem depends on the C extension of another Ruby gem, the only way
find the header of that gem is to run a Gem::Specification.find_by_name in the extconf.rb
of the gem needing the header and then adding the folder containing the header relative to
that path.

This approach is error-prone for three reasons:

  • It relies on the gem developer to do the hard work of finding out exactly where the needed header file is located inside the sources of the gem.
  • It assumes that the location of header file will never change irrespective of gem releases.
  • The gem author then needs to re-dig the sources of the source gem to find where the header is now located.

This is a considerable maintainence burden, especially given that there is no 'standard' way
of keeping public header files for C extensions of ruby gems.

I propose a new approach that will allow a gem developer to specify the path of the public
C header files in a new attribute within Gem::Specification in the gemspec of the source
gem. Thus, if someone wants to use the public headers of a gem, they can simply add the
following lines to their extconf.rb:

spec = Gem::Specification.find_by_name 'source-gem-name', 'source-gem-version'
find_header("source_gem.h", *spec.c_headers)

The way the source gem can specify the header file in their source-gem-name.gemspec can
be like so: do |spec|
  # lots of other specs
  spec.c_headers = ["path/to/headers/1", "path/to/headers/2"]

Updated by nobu (Nobuyoshi Nakada) over 2 years ago

  • Status changed from Open to Third Party's Issue

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