On 5 Dec 2025, at 19:26, Dimitry Andric <[email protected]> wrote: > > On 5 Dec 2025, at 14:37, Brian Inglis via Cygwin <[email protected]> wrote: >> >> >> On 2025-12-05 02:18, Dimitry Andric via Cygwin wrote: >>> We're using Cygwin make to build several projects in parallel mode, e.g. >>> with -j 4 or sometimes higher settings, depending on the core count of >>> the machine. >>> Sporadically, and then I'm talking about "once a week" or so, random >>> jobs will fail with a non-repeatable error, and in _every_ case these >>> failures are preceded by a warning from make: >>> make[4]: warning: jobserver unavailable: using -j1. Add '+' to parent >>> make rule. >>> Obviously the "Add '+' to parent rule" is nonsensical, since simply >>> running exactly the same job again almost always works fine. But there >>> is something flaky about make's jobserver under Windows. >>> FWIW one machine I just observed this on has the make-4.4.1-2 package, >>> which should use the "pipe" jobserver, if I interpret >>> https://cygwin.com/pipermail/cygwin-announce/2023-March/010972.html >>> correctly. >>> Does anybody know a way to further debug this issue? It must be some >>> rare race condition... >> >> https://stackoverflow.com/questions/60702726/warning-jobserver-unavailable-using-j1-add-to-parent-make-rule > > Yeah, I've read all those FAQs. The problem isn't in our Makefiles, > since they run just fine on Linux. It's only on Windows under Cygwin > that they break. :) > > I'm fairly certain it's a make bug, but whether it's Windows specific, > or just a Cygwin issue, is not yet clear.
I just read https://cygwin.com/pipermail/cygwin-announce/2023-March/010972.html, which says: > The default version [4.4.1-1] is built with jobserver using FIFO and > the test version [4.4.1-2] using pipe. > In same complex corner case the previous 4.4-1 was reported to > fail and it is unclear if the pipe version is the solution > or just a side coincidence. > Please report any problem on any version. >From Marco's post it is not really clear what the failure was, but our Windows systems all run 4.4.1-2 since that is the latest version, so I'll try reverting some boxes to 4.4.1-1 to see if that helps. -Dimitry -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
