# Install oniguruma "No definition for oregexp\_initialize "

**URL:** <https://www.ruby-forum.com/t/install-oniguruma-no-definition-for-oregexp-initialize/158259>\
**Category:** Ruby\
**Created:** [January 21, 2009, 6:30am UTC](https://www.ruby-forum.com/t/install-oniguruma-no-definition-for-oregexp-initialize/158259 "2009-01-21T06:30:17Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mike-moscow](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/53a042/32.png) [@mike-moscow](https://www.ruby-forum.com/u/mike-moscow)\
**Post date:** [January 21, 2009, 6:30am UTC](https://www.ruby-forum.com/t/install-oniguruma-no-definition-for-oregexp-initialize/158259/1 "2009-01-21T06:30:17Z")

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when I run “gem install oniguruma”.

get the message "No definition for oregexp\_initialize "

how to initialize oregexp?

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<div class="post-metadata">

**Author:** ![mike-moscow](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/53a042/32.png) [@mike-moscow](https://www.ruby-forum.com/u/mike-moscow)\
**Post date:** [January 21, 2009, 2:01pm UTC](https://www.ruby-forum.com/t/install-oniguruma-no-definition-for-oregexp-initialize/158259/2 "2009-01-21T14:01:06Z")

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Mike M. wrote:

> when I run “gem install oniguruma”.
> 
> get the message "No definition for oregexp\_initialize "
> 
> how to initialize oregexp?

I think this means you need to install the oniguruma C library and its  
headers. You don’t say what platform you’re on, so it’s hard to be more  
specific about how to do that.

Alternatively, you could use Ruby 1.9.1 which has oniguruma built-in, as  
well as other features to make working with encodings easier (one of the  
main reasons for using Oniguruma previously).

alex