我在安装 mysql gem 时遇到问题。这是我的错误：
gem install mysql -v '2.9.1'
Building native extensions. This could take a while...
ERROR: Error installing mysql:
ERROR: Failed to build gem native extension.
current directory: /usr/local/rvm/gems/ruby-2.4.0/gems/mysql-2.9.1/ext/mysql_api
/usr/local/rvm/rubies/ruby-2.4.0/bin/ruby -r ./siteconf20170107-4120-x2dv85.rb extconf.rb
checking for mysql_ssl_set()... yes
checking for rb_str_set_len()... yes
checking for rb_thread_start_timer()... no
checking for mysql.h... yes
creating Makefile
To see why this extension failed to compile, please check the mkmf.log which can be found here:
/usr/local/rvm/gems/ruby-2.4.0/extensions/x86_64-linux/2.4.0/mysql-2.9.1/mkmf.log
current directory: /usr/local/rvm/gems/ruby-2.4.0/gems/mysql-2.9.1/ext/mysql_api
make "DESTDIR=" clean
current directory: /usr/local/rvm/gems/ruby-2.4.0/gems/mysql-2.9.1/ext/mysql_api
make "DESTDIR="
compiling mysql.c
mysql.c: In function ‘stmt_bind_result’:
mysql.c:1320:74: error: ‘rb_cFixnum’ undeclared (first use in this function)
else if (argv[i] == rb_cNumeric || argv[i] == rb_cInteger || argv[i] == rb_cFixnum)
^
mysql.c:1320:74: note: each undeclared identifier is reported only once for each function it appears in
mysql.c: At top level:
cc1: warning: unrecognized command line option "-Wno-self-assign"
cc1: warning: unrecognized command line option "-Wno-constant-logical-operand"
cc1: warning: unrecognized command line option "-Wno-parentheses-equality"
cc1: warning: unrecognized command line option "-Wno-tautological-compare"
Makefile:241: recipe for target 'mysql.o' failed
make: *** [mysql.o] Error 1
make failed, exit code 2
Gem files will remain installed in /usr/local/rvm/gems/ruby-2.4.0/gems/mysql-2.9.1 for inspection.
Results logged to /usr/local/rvm/gems/ruby-2.4.0/extensions/x86_64-linux/2.4.0/mysql-2.9.1/gem_make.out
当我sudo gem install mysql -v '2.9.1'尝试此命令时，它有效，我阅读了这一行来证明它的合理性......
sudo gem install mysql -v '2.9.1'
Building native extensions. This could take a while...
Successfully installed mysql-2.9.1
Parsing documentation for mysql-2.9.1
Done installing documentation for mysql after 0 seconds
1 gem installed
我不明白发生了什么以及如何解决这个问题。如果有人能帮助我...
mysql gem 是许多不喜欢 Ruby 2.4 中整数类型的统一 gem 之一。
不幸的是，由于 mysql gem 不再真正维护，我不会屏住呼吸更新版本。作为解决方法，您可以切换到 2.4 之前的 Ruby 版本，例如 Ruby 2.3.3。
或者，您可以切换到积极维护的 mysql2 gem，具有与 mysql gem 类似的 API，并且最新版本与 Ruby 2.4 兼容。