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

It looks like in Ubuntu that header is part of the libpq-dev package (at least in the following Ubuntu versions: 11.04 (Natty Narwhal), 10.04 (Lucid Lynx), 11.10 (Oneiric Ocelot), 12.04 (Precise Pangolin), 14.04 (Trusty Tahr) and 18.04 (Bionic Beaver)):

...
/usr/include/postgresql/libpq-fe.h
...

So try installing libpq-dev or its equivalent for your OS:

• For Ubuntu/Debian systems: sudo apt-get install libpq-dev
• On Red Hat Linux (RHEL) systems: yum install postgresql-devel
• For Mac Homebrew: brew install postgresql
• For Mac MacPorts PostgreSQL: gem install pg -- --with-pg-config=/opt/local/lib/postgresql[version number]/bin/pg_config
• For OpenSuse: zypper in postgresql-devel
• For ArchLinux: pacman -S postgresql-libs