On Mar 9 19:08, Sjors Gielen wrote: > I think I checked how Cygwin implements fork() a while ago, can't really > remember though. But on a fork(), do processes inherit all information > on dll's, et cetera? Or do they reload the dll and re-check the > addresses of entry points and all?
Very basically, the executable is started again via CreateProcess, then Cygwin copies the parent's data segments into the child. The important faxct here is that the actual load process of the child is done by the Windows loader. If you changed the Cygwin DLL in the meantime, the new process will load the new Cygwin DLL, not the old one. From there it goes downhill because the data layout of the new DLL is different from the layout in the old DLL loaded with the parent process. > I *think* this cygfoo1_2_3.dll system does not work with the Cygwin dll > itself, because that all still happens completely outside of Cygwin > scope Yes. This happens because we're using Windows API and thus Windows loader to load processes. The Windows API simply hasn't been designed to fork. That's why Cygwin has to do all the tricky and not very performant stuff before and after loading a process. Actually the native NT API is capable to fork a process and that's used, for instance, in Interix. However, Interix is its entire self-contained POSIX subsystem, distinct from Windows, while Cygwin processes are running inside of the Windows subsystem. Unfortunately important parts of the API used to attach a new process to the Windows subsystem are not documented. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
