Issue #8591 has been updated by phasis68 (Heesob Park).


The libmysql.lib included in the MySQL Connector/C 64 bit is not compatible with the mingw64-gcc compiler.

You need to generate mingw64 compatible libmysql.lib file.

To generate libmysql.lib file, you need gendef.exe, which can obtain from mingw-w64 distribution(I got from https://structure-svm-map.googlecode.com/files/svm-map-win.zip)

In the lib folder of the mysql connector, produce libmysql.lib with the following steps.

   gendef.exe libmysql.dll
 
   dlltool -v --dllname libmysql.dll --def libmysql.def --output-lib libmysql.lib

And running the normal gem install command.
   gem install mysql2 -v '0.3.12b6' -- --with-opt-dir="..."

NOTE: 
In case of MySQL Connector/C 6.1, due to the version comparison routine, you cannot use mysql2 module with the following exception.
    RuntimeError: Incorrect MySQL client library version! This gem was compiled for 5.7.2-m12 but the client library is 6.1.0.
    
You should use mysql-connector-c-6.0.2-winx64.msi in http://dev.mysql.com/downloads/connector/c/6.0.html#downloads

----------------------------------------
Bug #8591: [BUG] Segmentation fault  ruby 2.0.0p195 (2013-05-14) [x64-mingw32]
https://bugs.ruby-lang.org/issues/8591#change-40266

Author: chmel (Josef Chmel)
Status: Third Party's Issue
Priority: Urgent
Assignee: cruby-windows
Category: platform/windows
Target version: 
ruby -v: ruby 2.0.0p195 (2013-05-14) [x64-mingw32]
Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN


rails server crashes with Segmentation fault
in pure app created with rails new . 
after installing mysql2 gem like this
gem install mysql2 -v '0.3.12b6' -- --with-opt-dir="C:\work\mysqlconnectorc61"

On Windows 7 64b with ruby 2.0 64b in C:\Ruby200-x64 installed by ruby installer rubyinstaller-2.0.0-p195-x64.exe, devkit DevKit-mingw64-64-4.7.2-20130224-1432-sfx.exe and mysql connector mysql-connector-c-6.1.0-winx64.msi.

without gem 'mysql2', '~>0.3.12b6' with gem 'sqlite3' server runs fine


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