# Installing ruby-postgres gem

**URL:** <https://www.ruby-forum.com/t/installing-ruby-postgres-gem/159697>\
**Category:** Rails\
**Created:** [February 7, 2009, 7:32am UTC](https://www.ruby-forum.com/t/installing-ruby-postgres-gem/159697 "2009-02-07T07:32:26Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![captaffy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/f04885/32.png) [@captaffy](https://www.ruby-forum.com/u/captaffy)\
**Post date:** [February 7, 2009, 7:32am UTC](https://www.ruby-forum.com/t/installing-ruby-postgres-gem/159697/1 "2009-02-07T07:32:26Z")

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I’m starting to look at postgres because I’m going to need it for its  
GIS extensions. But I run in into a problem when trying to install the  
ruby-postgres gem. I get this error

Building native extensions. This could take a while…  
ERROR: Error installing ruby-postgres:  
ERROR: Failed to build gem native extension.  
blah  
blah  
blah etc  
postgres.c:31: error: conflicting types for ‘pg\_encoding\_to\_char’  
/usr/include/postgresql/libpq-fe.h:518: error: previous declaration of  
‘pg\_encoding\_to\_char’ was here  
postgres.c: In function ‘pgconn\_s\_escape\_bytea’:  
postgres.c:370: warning: pointer targets in passing argument 1 of  
‘PQescapeBytea’ differ in signedness  
postgres.c: In function ‘pgconn\_s\_unescape\_bytea’:  
postgres.c:401: warning: pointer targets in passing argument 1 of  
‘PQunescapeBytea’ differ in signedness  
make: \*\*\* [postgres.o] Error 1

Presumably some people have installed Postgresql and got it to work with  
Ruby. Does anyone have any experience solving this problem?

Thanks

John S.

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<div class="post-metadata">

**Author:** ![captaffy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/f04885/32.png) [@captaffy](https://www.ruby-forum.com/u/captaffy)\
**Post date:** [April 8, 2009, 6:40pm UTC](https://www.ruby-forum.com/t/installing-ruby-postgres-gem/159697/2 "2009-04-08T18:40:21Z")

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change /usr/include/libpq-fe.h (extern const char  
\*pg\_encoding\_to\_char(int encoding); to extern char  
\*pg\_encoding\_to\_char(int encoding)😉 # remove const

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<div class="post-metadata">

**Author:** ![captaffy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/f04885/32.png) [@captaffy](https://www.ruby-forum.com/u/captaffy)\
**Post date:** [April 9, 2009, 7:56am UTC](https://www.ruby-forum.com/t/installing-ruby-postgres-gem/159697/3 "2009-04-09T07:56:50Z")

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Jorge Queiruga wrote:

> change /usr/include/libpq-fe.h (extern const char  
> \*pg\_encoding\_to\_char(int encoding); to extern char  
> \*pg\_encoding\_to\_char(int encoding)😉 # remove const

Thanks for that I’ve already switched to using the newer ruby-pg gem and  
that seems OK.

Ta

John S.