Win32s

Win32s is a system extension for Microsoft Windows 3.1 and Windows for Workgroups that can also be run as a Win-OS/2 task with OS/2 Warp Version 3 or higher. It installs support for 32-bit executables and 4 new APIs that prior to that had only been available in Windows NT and therefore allows for binary application portability between Windows NT and Windows 3.x.

The Windows 95 control classes are supported in applications running under Windows NT 3.51, Windows 95, and Win32s 1.3.