On 2008 Aug 31, at 13:20, Ganesh Sittampalam wrote:
On Sun, 31 Aug 2008, Brandon S. Allbery KF8NH wrote:
On 2008 Aug 31, at 12:01, Ganesh Sittampalam wrote:
On Sun, 31 Aug 2008, Brandon S. Allbery KF8NH wrote:
Where do the filehandle structures live in the latter case? The place you clearly think so little of that you need to ask:
On 2008 Aug 31, at 11:20, Ganesh Sittampalam wrote: process-global (or process-local depending on how you think about it) storage. And everything in that storage must have locking.
You'll have to look at specific implementations. One that I can think of off the top of my head is Perl 5's "ithreads"; there is a distinguished allocation store which is global to all ithreads, and the interpreter instance gives you primitives for locking and mutexing (see "use threads::shared;").
I'm afraid I don't see how this generalises to sharing something across an entire process where the things that want to do the sharing are not in or controlled by the same shared library. In particular the filehandle structures required for buffered I/O need to be common to every single piece of code in the process that might want to use them, no matter what language or language implementation that code uses.
For that you probably want to look at how ld.so.1 and libc interact to share the malloc pool and the stdin/stdout/stderr, among others. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH