Issue #6421 has been updated by luislavena (Luis Lavena). Status changed from Open to Assigned Assignee set to usa (Usaku NAKAMURA) Hello, According to the wiki, zlib has no maintainer: http://bugs.ruby-lang.org/projects/ruby/wiki/Maintainers Was my understanding that zlibwapi exported symbols as stdcall and not cdecl. Assigning to Usaku Nakamura. ---------------------------------------- Feature #6421: Add zlibwapi to extconf.rb file for zlib library https://bugs.ruby-lang.org/issues/6421#change-26574 Author: djberg96 (Daniel Berger) Status: Assigned Priority: Normal Assignee: usa (Usaku NAKAMURA) Category: ext Target version: 1.9.3 The vstudio contrib solution in zlib 1.2.7 creates a "zlibwapi" dll file. According to the readme.txt file, "The new DLL was renamed because there exist several incompatible versions of zlib.dll on the Internet." So, I propose this very modest adjustment to the extconf.rb file for zlib: -if %w'z libz zlib1 zlib zdll'.find {|z| have_library(z, 'deflateReset')} and +if %w'z libz zlib1 zlib zdll zlibwapi'.find {|z| have_library(z, 'deflateReset')} and Regards, Dan -- http://bugs.ruby-lang.org/