{"id":573,"date":"2006-12-14T00:39:55","date_gmt":"2006-12-14T05:39:55","guid":{"rendered":"http:\/\/blogs.law.harvard.edu\/hoanga\/2006\/12\/14\/getting-a-ruby-c-extension-to-compile-"},"modified":"2006-12-14T00:39:55","modified_gmt":"2006-12-14T05:39:55","slug":"getting-a-ruby-c-extension-to-compile-on-windows","status":"publish","type":"post","link":"https:\/\/archive.blogs.harvard.edu\/hoanga\/2006\/12\/14\/getting-a-ruby-c-extension-to-compile-on-windows\/","title":{"rendered":"Getting a Ruby C extension to compile on Windows"},"content":{"rendered":"

\nThe Programming Ruby<\/a> book is one of those must have references if you’re going to program Ruby. I still use it all the time when I’m looking up information on Ruby. One thing I’ve started playing with is getting a C extension to work with Ruby. Chapter 21 of Volume 2 of Programming Ruby<\/a> gives you a great example for writing a C extension from scratch and getting it to compile and work in a UNIX-based environment however it falls short on handholding you through the Windows process. Here’s my notes on what you need:\n<\/p>\n

Executive Summary<\/h3>\n
    \n
  1. Install Visual Studio Express<\/a> or some other Visual C++ variant<\/li>\n
  2. Install the Platform SDK<\/a> (You need this if you want windows.h<\/em> and you DO)<\/li>\n
  3. Make minor changes in Ruby config.h (Not necessary for all versions of Visual Studio)<\/li>\n
  4. Write the MyTest code and extconf.rb file from the book<\/li>\n
  5. Run ruby extconf.rb<\/em> to generate a nmake-based Makefile<\/li>\n
  6. Startup a command prompt with the SDK environment variables set<\/li>\n
  7. Run nmake<\/em> to compile the library<\/li>\n
  8. Done!<\/li>\n<\/ol>\n

    The detailed version<\/h3>\n

    Download Visual Studio<\/h4>\n

    Unless you’re using cygwin or mingw as your compiler you’ll probably want to get Visual Studio. The latest incarnation is Visual Studio 2005<\/a> which is a free download. I’ve found that it’s a pain to find the right URL to download it from on Microsoft but that’s Microsoft for you.<\/p>\n

    Download the Windows Platform SDK<\/h4>\n

    Since the Windows version of Ruby ties in with many Win32 libraries it’s necessary to get the Platform SDK<\/a>. If you DON’T download it you will see strange error messages when trying to compile your Ruby extension such as this:<\/p>\n

    \n
    \r\nc:\\ruby\\lib\\ruby\\1.8\\i386-mswin32\\win32\/win32.h(32) : fatal error C1083: Cannot\r\nopen include file: 'windows.h': No such file or directory\r\nNMAKE : fatal error U1077: '\"C:\\Program Files\\Microsoft Visual Studio 8\\VC\\BIN\\cl.EXE\"' : return code '0x2'\r\nStop.\r\n<\/pre>\n<\/blockquote>\n
    windows.h<\/em> is NOT included by default in Visual Studio 2005 (but I believe it is in older versions of Visual Studio) so you need the platform SDKs to get the right development libraries.  While it would be nice if the C-based version of Ruby could easily hook into the .Net platform, this would probably require significant hacking the mkmf<\/em> library in Ruby to get it to work transparently.  I doubt that will happen soon.<\/p>\n
    \nOnce again, I found Microsoft’s website really annoying to navigate in order to try to find the Platform SDK so you might want to click here<\/a> then make sure you have the latest platform SDK (As of this writing the latest was R1)\n<\/p>\n
    Tweak $RUBY_HOME\/lib\/ruby\/1.8\/i386-mswin32\/config.h<\/h4>\n
    For some versions Visual Studio (noteably Visual Studio 2005), the config file located in  $RUBY_HOME\/lib\/ruby\/1.8\/i386-mswin32\/config.h  (Usually $RUBY_HOME installs to C:\/Ruby) will  require a tweak to allow compilation.  Or you could rebuild Ruby from scratch yourself but I prefer to use the All-in-one installer<\/a>.  In the config.h file delete or comment out the following lines:<\/p>\n
    \n
    \r\n#if _MSC_VER != 1200\r\n#error MSC version unmatch\r\n#endif\r\n<\/pre>\n<\/blockquote>\n
    Finally!  Let’s compile it already<\/h4>\n
    Okay now you’re ready to finally to actually compile your code.  In order to get all the environment variables set properly you might want to launch a command prompt from the shortcuts the Platform SDK makes in the Start Menu then make sure to run vsvars32.bat from Visual Studio’s directory (Usually in C:\\Program Files\\Microsoft Visual Studio 8\\VC\\bin<\/em>).  Now with that all set you can finally compile something!  (whew!):<\/p>\n
    \n
    \r\nC:\\cygwin\\home\\foo\\exttest>ruby extconf.rb\r\ncreating Makefile\r\n\r\nC:\\cygwin\\home\\foo\\exttest>nmake\r\n\r\nMicrosoft (R) Program Maintenance Utility Version 8.00.50727.42\r\nCopyright (C) Microsoft Corporation.  All rights reserved.\r\n\r\n        cl -nologo -I. -Ic:\/ruby\/lib\/ruby\/1.8\/i386-mswin32 -Ic:\/ruby\/lib\/ruby\/1.\r\n8\/i386-mswin32 -I. -MD -Zi -O2b2xg- -G6  -c -Tcmy_test.c\r\ncl : Command line warning D9035 : option 'Og-' has been deprecated and will be r\r\nemoved in a future release\r\ncl : Command line warning D9002 : ignoring unknown option '-G6'\r\nmy_test.c\r\n        cl -nologo -LD -Femy_test.so my_test.obj msvcrt-ruby18.lib  oldnames.lib\r\n user32.lib advapi32.lib wsock32.lib  -link -incremental:no -debug -opt:ref -opt\r\n:icf -dll -libpath:\"c:\/ruby\/lib\" -def:my_test-i386-mswin32.def -implib:my_test-i\r\n386-mswin32.lib -pdb:my_test-i386-mswin32.pdb\r\n   Creating library my_test-i386-mswin32.lib and object my_test-i386-mswin32.exp\r\n\r\nC:\\cygwin\\foo\\exttest>irb\r\nirb(main):001:0> require 'my_test'\r\n=> true\r\nirb(main):002:0> test = MyTest.new\r\n=> #\r\n<\/pre>\n<\/blockquote>\n
    References<\/h3>\n