RE: MIT shared memory extension

["Robert Collins" <robert dot collins at itdomain dot com dot au>]

> -----Original Message-----
> From: Ralf Habacker [mailto:Ralf.Habacker@freenet.de] 
> Sent: Saturday, May 04, 2002 8:55 PM
> To: Robert Collins; Charles Wilson
> Cc: cygwin-xfree@cygwin.com
> Subject: RE: MIT shared memory extension
> 
> 
> > > the cygwin-daemon code was recently merged into CVS; the 
> snapshots 
> > > have the functionality but the daemon itself is not "turned on" by
> > > default.
> > > Just like ipcdaemon.exe, you have to start up the cygwin-daemon
> > > yourself.  For more info, see the cygwin-developers mailing
> > > list archives.
> >
> > cygdaemon provides ipc and shm, but the shm is incomplete. Someone 
> > want to fund it? (only half kidding).
> 
> Can you explain this a little bit more ?

I've got very little spare time at the moment. To devote more to Cygwin,
I'd need to allocate consulting time from my employer, and my employer
will want money to do that. I will eventually get it done on my own time
however.
 
> > As for it being turned on, you need to patch newlib (for 
> the new key_t
> > definition)
> 
> Could this perhaps not be patched in the cvs or are there 
> compatibility issues against it ?

The definition of key_t in newlib is a 32bit int, for cygdaemon it needs
to be 64 bit to store the inode and the index cleanly. Redefining that
will break every cygipc linked application when they are rebuilt, until
cygipc is rebuilt against the new source. However rebuilding cygipc will
break every already linked app. So until the cygdaemon shm code is
complete, Chuck and I figured that it was not worth putting everyone
through the agony of a backwards incompatible ABI change.
 
> > and cygwin (to export the functions)
> 
> all shm* symbols ?

Index: cygwin.din
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/cygwin.din,v
retrieving revision 1.44
diff -u -p -r1.44 cygwin.din
--- cygwin.din  2002/02/25 17:47:46     1.44
+++ cygwin.din  2002/03/03 21:52:10
@@ -1246,3 +1246,8 @@ acltotext
 _acltotext = acltotext
 aclfromtext
 _aclfromtext = aclfromtext
+ftok
+shmat
+shmctl
+shmdt
+shmget

Rob