Can't find the 'libpq-fe.h header when trying to install pg gem

Question

I am using the Ruby on Rails 3.1 pre version. I like to use PostgreSQL, but the problem is installing the pg gem. It gives me the following error:

Answer 1

I found this answer, and it was the only one that worked for me (Mac OS) - after researching for about two days:

$ sudo su

$ env ARCHFLAGS="-arch x86_64" gem install pg

Building native extensions.  This could take a while...
Successfully installed pg-0.11.0
1 gem installed
Installing ri documentation for pg-0.11.0...
Installing RDoc documentation for pg-0.11.0...

See Stack Overflow question Can't find the PostgreSQL client library (libpq).

Answer 2

The right answer for Mac users with Postgres.app is to build against the libpq provided with that package. For example, with the 9.4 release (current as of this writing), all you need is:

export CONFIGURE_ARGS="with-pg-include=/Applications/Postgres.app/Contents/Versions/9.4/include"
gem install pg

This will keep your pg gem in sync with exactly the version of PostgreSQL you have installed. Installing something from Homebrew is a waste in this case.

Answer 3

On Debian 7.0, 64-bit (Wheezy), just run:

sudo apt-get install libpq-dev

After you successfully installed libpq-dev, run:

bundle install

Answer 4

I encountered the same error with postgres installed through asdf. The pg-config solutions didn't work for me. Instead I had to locate the postgres include folder which contains the file and run the command with the --with-pg-include flag

gem install pg -- --with-pg-include=/<path>/.asdf/installs/postgres/<version>/include

Answer 5

I am running Postgres.app on a Mac and I had to

export PATH=$PATH:/Applications/Postgres.app/Contents/Versions/9.4/bin

first. Then

bundle install

worked for me.

Answer 6

My solution for Fedora 30:

sudo dnf install /usr/include/libpq-fe.h