gem install rails error solution

On windows 7 (x64)

When you install rails like this,

gem install rails

if you see errors

...

http://rubyinstaller.org/downloads -> Download Devkit!

http://github.com/oneclick/rubyinstaller/wiki/Development-Kit -> Manual

...

let's install Development-Kit.

Example Native RubyGem Installations using the DevKit

Once you’ve installed the DevKit you’ll discover there are but a few different types of native installation scenarios to deal with.

• The Typical Install Scenario – most of the native RubyGems you’re likely to encounter can be installed by running something similar togem install bson_ext --platform=ruby. It’s crucial that you include the --platform=ruby option to force RubyGems to build the native gem rather than potentially installing an incorrect binary gem.

• The Manual Install Scenario – sometimes a native RubyGem requires additional artifacts to already exist on your system and be usable. One such gem is curb which requires curl’s native header and library files in order be built and installed. In this scenario you need to tell RubyGems where to find those headers and library files by using a command similar togem install curb --platform=ruby -- --with-curl-lib="C:/curl/bin" --with-curl-include="C:/curl/include". In addition, the curl library found in the directory specified with --with-curl-lib must be on your PATH for use at runtime by the curb gem.

• The Hacky Developer Scenario – a developer building native gems wants to be able to quickly test that their extconf.rb file used to create a Makefile for the native library works correctly. To shorten the development cycle, the DevKit enables the developer to runruby -rdevkit extconf.rb.

After install Devkit, try it again

gem install rails

but!!! you could see below... :(

 Couldn't reserve space for cygwin's heap, Win32 error 0. ERROR: Error installing rdiscount: ERROR: Failed to build ...

It caused by msys-1.0.dll. You can change this from here.

http://support.code-red-tech.com/CodeRedWiki/VirtualAllocPointerNull

1. Download msys-1.0.zip

2. Unzip

3. Change the dll into <devkit directory>/bin/msys-1.0.dll

4. Done!!!