gem安装pg遇到问题安装pg遇到问题
#gem install pg
报错信息为：
building native extensions. this could take a while...
error: error installing pg:
error: failed to build gem native extension.
/usr/bin/ruby extconf.rb
checking for pg_config... yes
using config values from /usr/bin/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
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib64
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/usr/bin/ruby
--with-pg
--without-pg
--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}/
gem files will remain installed in /home/oss/.gem/ruby/gems/pg-0.17.1 for inspection.
results logged to /home/oss/.gem/ruby/gems/pg-0.17.1/ext/gem_make.out
#=============================================================
说明：
注意看上边的报错信息（如下边这样的语句）：
checking for libpq-fe.h... no
can't find the 'libpq-fe.h header
你安装其他gem插件的时候也会遇到类似这样的问题，找不到什么什么.h这样的文件，就是缺少你安装的这个gem包的依赖包，一般都是安装xxxx-devel就能解决问题。
例如我遇到的这个问题，安装postgresql这个数据库的依赖包就行了postgresql-devel，具体执行下面的命令即可
#===================================================================
解决方法：
安装postgresql数据库的依赖包
#yum install postgresql-devel
安装好以后再安装pg这个gem包
#gem install pg
ok，搞定