It is, however, according to Charlie Savage, possible to mix code built from newer compilers into it [1].
Mixing runtime libraries
========================
The most obvious criticism of this plan is that it will lead to mixing of microsoft runtime c libraries. From my experience this works as long as extension developers follow the rules described here:
http://msdn.microsoft.com/en-us/library/ms235460(VS.80).aspx
To be more concrete, this boils down to two simple rules:
* If you call ALLOC or ALLOC_N, use xfree and not free
* Don't call sprintf or printf in an extension, instead use rb_f_sprintf/rb_vsprintf/rb_io_printf
If an extension violate these two rules then its obvious, a segmentation fault happens. Thus these bugs are easy to find and easy to fix.
Since VC6 is thankfully no longer available, supporting msvc absolutely, positively requires mixing c runtime libraries and therefore extension writers must follow these two simple rules.
========================
The most obvious criticism of this plan is that it will lead to mixing of microsoft runtime c libraries. From my experience this works as long as extension developers follow the rules described here:
http://msdn.microsoft.com/en-
To be more concrete, this boils down to two simple rules:
* If you call ALLOC or ALLOC_N, use xfree and not free
* Don't call sprintf or printf in an extension, instead use rb_f_sprintf/rb_vsprintf/rb_
If an extension violate these two rules then its obvious, a segmentation fault happens. Thus these bugs are easy to find and easy to fix.
Since VC6 is thankfully no longer available, supporting msvc absolutely, positively requires mixing c runtime libraries and therefore extension writers must follow these two simple rules.
(Note that if you use rb_x_malloc and its siblings, they will use the right free call for you).
i.e. (summarizing) "If it uses ALLOC, xfree, doesn't use STDIN/STDOUT, it can link against any runtime it wants" [though nobu did note there may be a problem with errno's differing, probably not a problem.]
That being said it would appear that you need to also avoid the /MD compiler directive in MS compilers, as well [2].
Also, users may need to download a redistributable for the version of C compiler you used.
However, it should work.
Note that for distributing gems, you can use Luis Lavena's "rake compiler" to build your binaries for you [3].
Good luck!
[1] http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/22727
[2] http://groups.google.com/group/thin-ruby/browse_thread/thread/c15b2472eb97c2ba/ea7c5127035d193b
[3] http://github.com/luislavena/rake-compiler/tree/master ex: ext.cross_platform = ['i386-mswin32', 'i386-mingw32']
