Gems install failed

Hello,

Sorry I’m totally new in ruby and gems.
I installed a module via gems failed this day. The error shows:

gem install cassandra

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

/usr/bin/ruby1.8 extconf.rb
extconf.rb:21:in `require’: no such file to load – mkmf (LoadError)
from extconf.rb:21

Gem files will remain installed in
/var/lib/gems/1.8/gems/thrift-0.2.0.4 for inspection.
Results logged to /var/lib/gems/1.8/gems/thrift-0.2.0.4/ext/gem_make.out

I’m running ruby-1.8 in ubuntu 9.10.
How to fix it? thanks.

Sorry I have got it installed correctly.
Coz I shall install ruby1.8-dev firstly.

But another question:

irb(main):003:0* require ‘rubygems’
=> true
irb(main):004:0> require ‘cassandra’
=> true

what’s the purpose of require ‘rubygems’?
I found that if I didn’t require rubygems then require cassandra will
get fail.

Thanks.

2010/11/1 wroxdb [email protected]:

On 10/31/2010 10:13 PM, wroxdb wrote:

what’s the purpose of require ‘rubygems’?
I found that if I didn’t require rubygems then require cassandra will get fail.

In the version of Ruby you’re using, the rubygems module is not loaded
by default. Without rubygems loaded, the require method does not know
how to find your gems when you try to require them. Ruby 1.9 loads
rubygems by default, so it’s optional to do so there.

If you don’t want to explicitly require rubygems in your script, you can
also set an environment variable named RUBYOPT as follows to cause your
version of Ruby to load it automatically:

export RUBYOPT=-rubygems

Keep in mind that this environment variable would have to be set any
time you want to run your script with Ruby 1.8.

-Jeremy

version of Ruby to load it automatically:

export RUBYOPT=-rubygems

Keep in mind that this environment variable would have to be set any
time you want to run your script with Ruby 1.8.

-Jeremy

OK Thanks a lot.