On Tue 28 Apr 2015 at 09:20:11 -0400, Clem Cole wrote: > Hmm, the PWD 3.0/System V later Posix shm(2) functions I would have > expected NetBSD to have picked up by now I agree.
Do you mean shmat(2), shmdt(2), shmget(2), etc? NetBSD has those. Just not yet the newer shm_open(3). It's a different kind of shared memory anyway: it persists after all processes that use it have terminated. The descriptors are not file descriptors. > But no matter, I believe you can use the mmap(2) mechanism if you want > shared memory in BSD post 4.4. A potential worry with mmap(2) might be about how immediately a change in mapped memory is visible in the other processes, if you use mmap on a random file. The existence of the msync(2) system call makes this worrisome, altough the manual pages don't seem to address this one way or another. NetBSD's new-in-version-7 shm_open(3) function actually uses a normal file, but on a ram disk file system. I'm not sure if this is for performance reasons, or to guarantee immediate visibility between processes. See http://cvsweb.netbsd.org/bsdweb.cgi/src/lib/librt/shm.c?only_with_tag=HEAD . -Olaf. -- ___ Olaf 'Rhialto' Seibert -- The Doctor: No, 'eureka' is Greek for \X/ rhialto/at/xs4all.nl -- 'this bath is too hot.'
pgpLF1ZmM_Q2p.pgp
Description: PGP signature
_______________________________________________ Simh mailing list [email protected] http://mailman.trailing-edge.com/mailman/listinfo/simh
