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. -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
