问题
Hey I'm trying to install rails on a new ubuntu machine. I have ruby and rvm installed but I'm getting a "failed to build gem native extension" error. What does this mean?
$ sudo gem install rails -v 3.2.9
(without the sudo says I don't have permissions)
Then it outputs a lot of 'fetching' commands and ultimately this error:
Building native extensions. This could take a while...
ERROR: Error installing rails:
ERROR: Failed to build gem native extension.
/usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from extconf.rb:1:in `<main>'
Gem files will remain installed in /var/lib/gems/1.9.1/gems/json-1.8.0 for inspection.
Results logged to /var/lib/gems/1.9.1/gems/json-1.8.0/ext/json/ext/generator/gem_make.out
When I type
$rails server
It says rails is not currently installed
回答1:
Possible duplicate of:
Unable to install gem - Failed to build gem native extension - cannot load such file -- mkmf (LoadError)
Depending on your ruby version, run:
sudo apt-get install ruby1.9.1-dev
回答2:
If you are using RVM, you shouldn't ever be using 'sudo'. Using sudo calls libs and such out of the rvm path. Try just a flat:
gem install rails -v3.2.9
and see if that helps.
来源：https://stackoverflow.com/questions/18316667/failed-to-build-gem-native-extension-mkmf-loaderror-ubuntu-12-04