# Optional libraries : openssl, readline, zlib, what is needed

**URL:** <https://www.ruby-forum.com/t/optional-libraries-openssl-readline-zlib-what-is-needed/85725>\
**Category:** Ruby\
**Created:** [February 15, 2007, 9:06pm UTC](https://www.ruby-forum.com/t/optional-libraries-openssl-readline-zlib-what-is-needed/85725 "2007-02-15T21:06:07Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![AnSSS\_bal](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c77e96/32.png) [@AnSSS\_bal](https://www.ruby-forum.com/u/AnSSS_bal)\
**Post date:** [February 15, 2007, 9:06pm UTC](https://www.ruby-forum.com/t/optional-libraries-openssl-readline-zlib-what-is-needed/85725/1 "2007-02-15T21:06:07Z")

</div>

Hello,

```
Is there a way to know what are the optional libraries should be

```

installed to assure that a Ruby installation from sources comes out  
nicely with everything functional?

```
Common missing libraries in my experience, and web searches are:

```

zlib-devel (required by gems), openssl-devel required by Capistrano),  
readline-devel (required by IRB and the Rails Console)

```
If those libraries are not present, Ruby will be installed without

```

problem after ./configure, make and sudo make install, but later a lot  
of features will be missing.

```
Thanks in advance for any suggestion

```

–  
Aníbal Rojas

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---

<div class="post-metadata">

**Author:** ![AnSSS\_bal](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c77e96/32.png) [@AnSSS\_bal](https://www.ruby-forum.com/u/AnSSS_bal)\
**Post date:** [February 16, 2007, 11:27pm UTC](https://www.ruby-forum.com/t/optional-libraries-openssl-readline-zlib-what-is-needed/85725/2 "2007-02-16T23:27:22Z")

</div>

“Aníbal” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

> Hello,
> 
> ```
> Is there a way to know what are the optional libraries should be
> 
> ```
> 
> installed to assure that a Ruby installation from sources comes out  
> nicely with everything functional?

There seems to be a lot of room for interpretation there.

> ```
> Common missing libraries in my experience, and web searches are:
> 
> ```
> 
> zlib-devel (required by gems), openssl-devel required by Capistrano),  
> readline-devel (required by IRB and the Rails Console)

It seems like you already have the list given your own interpretation.

> ```
> If those libraries are not present, Ruby will be installed without
> 
> ```
> 
> problem after ./configure, make and sudo make install, but later a lot  
> of features will be missing.
> 
> ```
> Thanks in advance for any suggestion
> 
> ```

One nice thing to do (given my own interpretation) is to look through  
the ext directory and see what dependencies are _possible_, then  
either pick what’s important to you, or just go for maximum coverage.  
Directories in ext/ tend to be named such that either they have  
obvious external dependencies (ext/openssl, ext/readline, ext/tk), or  
no external dependencies (ext/syck). For even more detail, you can  
look at the extconf.rb file in each ext directory, e.g.

[/src/lang/ruby/core/ruby-1.8.5-p12]0% cat ext/curses/extconf.rb  
require ‘mkmf’

dir\_config(‘curses’)  
dir\_config(‘ncurses’)  
dir\_config(‘termcap’)  
[…]

(So now you know the curses extension will work with curses or  
ncurses.)

Steve