On FreeBSD, libobjc has always used POSIX threads. The abstraction layer includes Mach, Irix, and Solaris back ends. All of these platforms now have a POSIX-compliant threading library (and have got about a decade). There are no platforms on which GNUstep runs that do no either support POSIX threads or get POSIX threads through the same POSIX-compatibility framework needed for the rest of GNUstep.

This is one of the reasons why the new runtime uses pthreads directly. The abstraction layer in the GNU runtime is almost as big as the entire codebase for the new runtime.

Possibly ... but the threading layer is all implemented and very stable and actively used - and provides nice flexibility in porting the Objective-C runtime to different machines. Any special reason for removing this flexibility and future-proofing - other than
that you might have found a bug in the code ?

Btw, when you compile the GNU Objective-C runtime as part of GCC, it automatically uses GCC's own internal abstraction layer for threads. In that case, the abstraction layer is a single trivial file that just remaps all functions to GCC's own internal abstraction layer ones. ;-)

If you compile the GNU Objective-C runtime standalone, yes you do get a bunch of different threading implementations; I think the two that are more likely to be in use are the posix one and the win32 one. If we removed the abstraction layer, how would we deal with the win32 one ? It's nice to be able to use native Windows threads on Windows. Were you thinking of using some posix-layer on top
of the win32 threads ?

Anyway, my favourite reason for having the abstraction layer is the ability to disable threads on a platform without changing any of the frameworks. If you configure the abstraction layer to use thr- single, you can then compile and use everything on top of it in single-thread mode with no threading library installed. It also sounds quite useful if someone is porting Objective-C stuff to some future architecture or machine where threads are not available, or there is no threading library - or they just want to get stuff working single-threaded first and deal with thread complications later. :-)

Anyway given that the abstraction layer is all done for the most useful thread implementations (single, posix and win32) I'm not sure why
we'd want to remove it. ;-)

Thanks


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