title: Error Installing PG Gem on Windows
body: <p>I'm using XAMPP as my installation folder for PostgreSQL 9.3.</p>
  
  <blockquote>
    <p>C:\xampp\pgsql\9.3</p>
  </blockquote>
  
  <p>And now I'm trying to install PostgreSQL gem using that directory as a reference:</p>
  
  <pre><code>gem install pg -- --with-pg-include="C:\xampp\pgsql\9.3\include" --with-pg-lib="C:\xampp\pgsql\9.3\lib" --with-pg-config="C:\xampp\pgsql\9.3\bin\pg_config"
  </code></pre>
  
  <p>But this command failed with errors listed below:</p>
  
  <pre><code>ERROR:  Error installing pg:
          ERROR: Failed to build gem native extension.
  
      C:/Ruby/Ruby200/bin/ruby.exe extconf.rb --with-pg-include=C:\xampp\pgsql\9.3
  \include --with-pg-lib=C:\xampp\pgsql\9.3\lib --with-pg-config=C:\xampp\pgsql\9.
  3\bin\pg_config
  Using config values from C:\xampp\pgsql\9.3\bin\pg_config
  checking for libpq-fe.h... yes
  checking for libpq/libpq-fs.h... yes
  checking for pg_config_manual.h... yes
  checking for PQconnectdb() in -lpq... no
  checking for PQconnectdb() in -llibpq... no
  checking for PQconnectdb() in -lms/libpq... no
  Cant find the PostgreSQL client library (libpq)
  *** extconf.rb failed ***
  Could not create Makefile due to some reason, probably lack of necessary
  libraries and/or headers.  Check the mkmf.log file for more details.  You may
  need configuration options.
  
  Provided configuration options:
          --with-opt-dir
          --without-opt-dir
          --with-opt-include
          --without-opt-include=${opt-dir}/include
          --with-opt-lib
          --without-opt-lib=${opt-dir}/lib
          --with-make-prog
          --without-make-prog
          --srcdir=.
          --curdir
          --ruby=C:/Ruby/Ruby200/bin/ruby
          --with-pg
          --without-pg
          --with-pg-config
          --with-pg-dir
          --without-pg-dir
          --with-pg-include=${pg-dir}/include
          --with-pg-lib=${pg-dir}/
          --with-pqlib
          --without-pqlib
          --with-libpqlib
          --without-libpqlib
          --with-ms/libpqlib
          --without-ms/libpqlib
  
  extconf failed, exit code 1
  
  Gem files will remain installed in C:/Ruby/Ruby200/lib/ruby/gems/2.0.0/gems/pg-0
  .17.1 for inspection.
  Results logged to C:/Ruby/Ruby200/lib/ruby/gems/2.0.0/extensions/x86-mingw32/2.0
  .0/pg-0.17.1/gem_make.out
  </code></pre>
  
  <p>When I checked inside pgsql, there was actually a file named <strong>libpq.dll</strong> inside of</p>
  
  <blockquote>
    <p>C:\xampp\pgsql\9.3\lib</p>
  </blockquote>
  
  <p>So why did the error say it couldn't find the PostgreSQL client library (libpq)?? <br>
  Is there any solutions for this error? <br><br>
  FYI, I'm using: <br></p>
  
  <ul>
  <li>Windows    8.1   64-bit</li>
  <li>Ruby       2.0.0 64-bit</li>
  <li>Rails      4.1.1</li>
  <li>Devkit     4.7.2 64-bit</li>
  <li>PostgreSQL 9.3.4 64-bit</li>
  </ul>
  
  <p>And I'm trying to install PG Gem version 0.17.1</p>