Usage in Open Source in General Discussion Posted April 17, 2008 · Report reply As far as I understand its perfectly legal to compile GPL software with JET, because its a "basis framework", some kind of operating system. Its also legal to compile GPL apps with VC++ and distribute them and also to run GNU software on Windows You mix compilation and distribution. Simply put, GPL permits you to do whatever you want with the source code, the restrictions are on distribution. You may only redistribute GPL apps compiled with VC++ if you link to the VC++ runtime dynamically. The Excelsior JET Runtime contains our proprietary code and Sun code licensed under SCSL Commercial Use, which is not GPL-compatible.