Re: Make losing jobserver tokens on Windows

[Eli Zaretskii]

> From: Paul Smith <psmith@gnu.org>
> Date: Fri, 18 Feb 2022 10:04:08 -0500
> 
> I am not aware of any issues like this.  However, I recommend that you
> try using the Visual Studio build of GNU make and see if that works
> better.  I'm not very familiar with the Cygwin version of GNU make;
> it's not maintained by us but my understanding is that they've needed
> to apply some patches (maybe this understanding is outdated though).
> 
> I believe that the goal of the Cygwin port is to implement a POSIX
> layer on top of Windows, so I'm assuming that when you compile GNU make
> with Cygwin it uses the POSIX implementation of the jobserver.  This
> implementation relies on certain POSIX behaviors of pipes and signals
> and it's possible that the Cygwin wrappers here have an issue that is
> leading to this problem.
> 
> The Windows jobserver uses Windows semaphores: it's a simpler
> implementation than the POSIX one and may be more reliable since it's
> using a native W32 implementation.
> 
> Note, all the above is just my personal noodling based on no actual
> knowledge, as I'm not really a Windows person.
> 
> Maybe Eli will have some other thoughts.

Oops, I missed the fact that this was about the Cygwin port of Make.
If so, the pointer to the sources I gave was the wrong one, sorry.

Yes, Cygwin is supposed to emulate a Posix system (via its special
DLL).  For a Cygwin build of Make, I suggest to post a question to the
Cygwin mailing list, with the details you reported here.  They might
be more familiar with these issues than we are here.  It could be some
subtle issue with the way they emulate pipes and/or signals.