It appears, at first, to be a very dignified error message, very poised in telling you what exactly needs to happen and here you are thinking, oh look, it tells me what I have to do. Don’t let that fool you, I spent the better part of a evening trying to get past the above message.

Here is my stack trace:

Building native extensions.  This could take a while...
ERROR:  Error installing adhearsion:
ERROR: Failed to build gem native extension.

/home/karthicr/.rvm/rubies/ruby-2.0.0-p247/bin/ruby extconf.rb
checking for pcre.h... *** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
/home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:430:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:561:in `try_cpp'
from /home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:1085:in `block in find_header'
from /home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:891:in `block in checking_for'
from /home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:336:in `block (2 levels) in postpone'
from /home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:306:in `open'
from /home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:336:in `block in postpone'
from /home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:306:in `open'
from /home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:332:in `postpone'
from /home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:890:in `checking_for'
from /home/karthicr/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/mkmf.rb:1084:in `find_header'
from extconf.rb:5:in `<main>'

Gem files will remain installed in /home/karthicr/.rvm/gems/ruby-2.0.0-p247/gems/ruby_speech-2.3.0 for inspection.
Results logged to /home/karthicr/.rvm/gems/ruby-2.0.0-p247/gems/ruby_speech-2.3.0/ext/ruby_speech/gem_make.out

Long story short, I was trying to install adhearsion on my laptop running Ubuntu 12.04 LTS. I had never worked on ruby before so I set about installing:

  • rvm (using curl)
  • ruby (using rvm)
  • rubygems (using rvm)
  • adhearsion (using gem)

I was having trouble getting ruby_speech (an adhearsion dependency) compiled. After loads of googling and installing all sorts of packages you think will help you get past this error, I finally found the solution documented here: Can’t install ruby_speech gem, checking for pcre.h… no

All you need is this:

sudo apt-get install libpcre3 libpcre3-dev

And you are scott free! Cheers and happy coding!