gem install pg -v '0.18.2' Building native extensions. This could take a while... ERROR: Error installing pg: ERROR: Failed to build gem native extension. current directory: /Users/bevan/.rvm/gems/ruby-2.3.0/gems/pg-0.18.2/ext /Users/bevan/.rvm/rubies/ruby-2.3.0/bin/ruby -r ./siteconf20160226-49308-30rbgs.rb extconf.rb checking for pg_config... no No pg_config... trying anyway. If building fails, please try again with --with-pg-config=/path/to/pg_config checking for libpq-fe.h... no Can't find the 'libpq-fe.h header *** 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 --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=/Users/bevan/.rvm/rubies/ruby-2.3.0/bin/$(RUBY_BASE_NAME) --with-pg --without-pg --enable-windows-cross --disable-windows-cross --with-pg-config --without-pg-config --with-pg_config --without-pg_config --with-pg-dir --without-pg-dir --with-pg-include --without-pg-include=${pg-dir}/include --with-pg-lib --without-pg-lib=${pg-dir}/lib To see why this extension failed to compile, please check the mkmf.log which can be found here: /Users/bevan/.rvm/gems/ruby-2.3.0/extensions/x86_64-darwin-15/2.3.0/pg-0.18.2/mkmf.log extconf failed, exit code 1 Gem files will remain installed in /Users/bevan/.rvm/gems/ruby-2.3.0/gems/pg-0.18.2 for inspection. Results logged to /Users/bevan/.rvm/gems/ruby-2.3.0/extensions/x86_64-darwin-15/2.3.0/pg-0.18.2/gem_make.out
当出现如上的错误的时候，解决方法以下sql
ubuntu:ubuntu
1. sudo apt-get install libpq-dev
2. gem install pg
mac:windows
1. brew install postgresql
2. gem install pg -- --with-pg-config=/Applications/Postgres.app/Contents/Versions/9.4/bin/pg_config