[zmmmmm]

I'm not really an expert but I'm pretty sure you can call fork but you will pay a full cost of a creating a new process, manually copying the memory state to the new process and parent and child have to do a complicated dance to ensure it all happens right. So it works and most of the semantics are the same, but it is god awful slow.

[cplease]

> you can call fork but you will pay a full cost of a creating a new process, manually copying the memory state to the new process and parent and child have to do a complicated dance to ensure it all happens right

That fork() and associated dance happens in cygwin1.dll or the equivalent POSIX compatibility library. Windows has no fork to call.