# How to compile extensions in Visual Studio 2005 **URL:** \ **Category:** Ruby\ **Created:** [August 15, 2006, 2:20pm UTC](https://www.ruby-forum.com/t/how-to-compile-extensions-in-visual-studio-2005/64941 "2006-08-15T14:20:50Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![fangheuschrecke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/58956e/32.png) [@fangheuschrecke](https://www.ruby-forum.com/u/fangheuschrecke)\ **Post date:** [August 15, 2006, 2:20pm UTC](https://www.ruby-forum.com/t/how-to-compile-extensions-in-visual-studio-2005/64941/1 "2006-08-15T14:20:50Z")
Hi all, I found this a while ago (on an SAP mailing list, if I recall correctly) and I thought I share this. When compiling native extensions on windows using Visual Studio 2005, loading the resulting library results in an ungly Runtime Error. This seems to be caused by some information missing from the library, which is included automatically when using VC6. To fix this problem, execute mt.exe -outputresource:extension\_name.so;2 -manifest extension\_name.so.manifest Replacing extension\_name with the correct extension name, of course. I have modified my mkmf.rb file to include this line: mfile.print “\n\tmt.exe -outputresource:$(DLLIB);2 -manifest $(DLLIB).manifest” if $mswin right under mfile.print LINK\_SO So far, I have tested this for some of my own extensions, as well as ruby-debug. I also use it to try and compile the Ferret c extension, but am having some problems - but those are caused by problems with the Ferret code itself, not the extension loading mechanism. Cheers, Max ---
**Author:** ![fangheuschrecke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/58956e/32.png) [@fangheuschrecke](https://www.ruby-forum.com/u/fangheuschrecke)\ **Post date:** [August 15, 2006, 2:20pm UTC](https://www.ruby-forum.com/t/how-to-compile-extensions-in-visual-studio-2005/64941/2 "2006-08-15T14:20:54Z")
On 8/14/06, Max M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > When compiling native extensions on windows using Visual Studio 2005, > loading the resulting library results in an ungly Runtime Error. How? You don’t. Visual Studio 2005 does not produce extensions compatible with VC6 output. I ran out of time writing up stuff last week, but I will be sending something to Microsoft this week about this sort of issue. -austin ---
**Author:** ![fangheuschrecke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/58956e/32.png) [@fangheuschrecke](https://www.ruby-forum.com/u/fangheuschrecke)\ **Post date:** [August 15, 2006, 2:20pm UTC](https://www.ruby-forum.com/t/how-to-compile-extensions-in-visual-studio-2005/64941/3 "2006-08-15T14:20:58Z")
On 8/15/06, Austin Z. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > On 8/14/06, Max M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > When compiling native extensions on windows using Visual Studio 2005, > > loading the resulting library results in an ungly Runtime Error. > > How? You don’t. Visual Studio 2005 does not produce extensions > compatible with VC6 output. Did you read the post? It wasn’t a question… I am aware there are incompatibilities, however I have been able to compile some extensions quite successfully with VS2005. One of the problems (which is fixed by the mt.exe call in the OP) is that the libraries produced by VS2005 are apparently missing some metainformation. Another problem I have found through tinkering with Ferret is that in win32.h fclose() gets redefined to rb\_w32\_fclose(). rb\_w32\_fclose does not work in vs2005-compiled code, it only seems to want to close files that have been opened with the corresponding rb\_open. However, as Ferret makes extensive use of fseek(), for which there seems to be no rb\_\* equivalent, the only way for me to fix this currently appears to be by undefining fclose() before including stdio.h. This works perfectly for compiling Ferret. I tried compiling ruby-debug (works fine) and the rcov extension (no success). I fact, the current win32 gem for ruby-debug was compiled with VS2005. Max ---
**Author:** ![fangheuschrecke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/58956e/32.png) [@fangheuschrecke](https://www.ruby-forum.com/u/fangheuschrecke)\ **Post date:** [August 15, 2006, 4:38pm UTC](https://www.ruby-forum.com/t/how-to-compile-extensions-in-visual-studio-2005/64941/4 "2006-08-15T16:38:38Z")
On 8/15/06, Max M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Did you read the post? It wasn’t a question… I am aware there are > incompatibilities, Yes, I did. I’m trying to discourage anyone from using your instructions because they will ultimately come to _greater_ problems trying to use them because of what I consider to be stupid decisions by Microsoft toward SxS assemblies. The mt call you make only masks the problems that will arise. I strongly recommend that you do NOT mix Windows compiler versions. Doing so is just asking for trouble. -austin ---
**Author:** ![fangheuschrecke](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/58956e/32.png) [@fangheuschrecke](https://www.ruby-forum.com/u/fangheuschrecke)\ **Post date:** [August 16, 2006, 12:03am UTC](https://www.ruby-forum.com/t/how-to-compile-extensions-in-visual-studio-2005/64941/5 "2006-08-16T00:03:59Z")
> I strongly recommend that you do NOT mix Windows compiler versions. > Doing so is just asking for trouble. Fair enough. Is there a write-up anywhere detailing the changes that cause the incompatibilities? Max