Re: [Libguestfs] nbdkit / mingw support

Answering a few questions: * Unclear why it's necessary to rename nbdkit-common.h -> nbdkit-compat.h - It's not a rename, but a new file. nbdkit-compat.h is included for PE DLL compatibility, and is included in nbdkit-common.h * Functions are indirected through struct nbdkit_functions _nbdkit_functions which I guess is necessary because of PE linking (we've had similar problems with PE linking restrictions in other programs). However I wasn't very clear how this actually works, and we cannot break existing Linux binaries, so this needs more thought and must be conditional on Windows only. - There are macro checks for an windows environment. If it's windows, then indirection is used. Otherwise, the original extern definitions are used. This shouldn't cause an ABI change on Linux. * Is there no way to get the socket peer on Windows? - It's not a lack of ways that prevents me from implementing this. The nbdkit port is to MSYS2 (which is a superset of mingw-64), and this is needed because nbdkit uses an extensive set of POSIX features that are not present in mingw-64, e.g. fork). This port requires MSYS2 to run. However, the user might choose to implement the plugins / filters using mingw-64, or just MSVC runtime, and I don't want to bind users to MSYS2. Now this causes a potential ABI incompatibility: MSYS2 socket definitions are provided by sys/socket.h, but mingw-64 / MSVC socket definitions are usually provided by winsock.h or winsock2.h. To prevent possible issues, I removed nbdkit_peer_name. This function is not defined in the include headers if Windows is detected, so it will cause a compile time error if someone attempts to use it. On Sat, Mar 21, 2020 at 1:20 PM Richard W.M. Jones <rjones(a)redhat.com&gt; wrote: