erik@mpx2.UUCP (Erik Murrey) (01/05/89)
I would like to be able to send a signal, or an ioctl() request to "shl" to SWTCH to the layer manager. Well, as you can *just* imagine, my documentation for SXT's is about 1+1/2 pages... H*ll, the include file is longer than that! My question is: how does a session manager (i.e. "shl") receive the SWTCH hot-key from the tty driver? A quick glance through signal.h/sxt.h/termio.h reveals nothing. Does it just do a read on the controlling channel which blocks until SWTCH? In this particular case, c_cc[VSWTCH] has been reset to '\0' (I believe) so the application can use ^Z for something else.... This makes it totally impossible to switch to another layer. Please, no flames about SysV job control (what job control?)... I'm stuck with it... Thanks! -- Erik Murrey /| // /~~~~/ | / MPX Data Systems, Inc. / | / / /____/ |/ erik@mpx2.UUCP / / / / /| Data Systems, Inc. {spl1,vu-vlsi,bpa}!mpx1!erik / / / / |====================
friedl@vsi.COM (Stephen J. Friedl) (01/06/89)
In article <329@mpx2.UUCP>, erik@mpx2.UUCP (Erik Murrey) writes: > > I would like to be able to send a signal, or an ioctl() request to > "shl" to SWTCH to the layer manager. I think that this is not possible. We have used sxts moderately extensively, and we had to have a child send an agreed-upon signal to the manager to relinquish control. This is indeed a bummer -- it couldn't have been that hard to add to the driver [?]. > My question is: how does a session manager (i.e. "shl") receive the > SWTCH hot-key from the tty driver? A quick glance through > signal.h/sxt.h/termio.h reveals nothing. Does it just do a read on > the controlling channel which blocks until SWTCH? Once the layer manager has multiplexed all the children onto the real tty, it makes one current with SXTIOCSWTCH and then goes to sleep until it is current with SXTIOCWF. When the user hits control-Z, channel 0 is automatically made current. Since this is usually the manager, it prints its little >>> prompt and you can pick another layer. A couple of notes: (first) the SWTCH character -- control-Z, usually -- is never actually seen by either manager nor managed children, and (second) in no case are signals used in the entire sxt system outside of the normal killing of child processes upon the manager's request. SXTs are handy for a lot of things, and *we* couldn't live without them, but they are not job control. Steve P.S. - we inferred most of what we know by lots and lots and lots of T&E. Anybody with *real* information is certainly encouraged to correct the bugs that may lurk within the above. Someday I'll have to go back to school so I can look at source again :-). -- Stephen J. Friedl 3B2-kind-of-guy friedl@vsi.com V-Systems, Inc. I speak for me only attmail!vsi!friedl Santa Ana, CA USA +1 714 545 6442 {backbones}!vsi!friedl -------Nancy Reagan on Usenix in San Diego: "Just say *go*"-------
erik@mpx2.UUCP (Erik Murrey) (01/07/89)
[ it seems that my postings aren't making it out, so here goes again.. please excuse if you have already seen this... ] I would like to be able to send a signal, or an ioctl() request to "shl" to SWTCH to the layer manager. Well, as you can *just* imagine, my documentation for SXT's is about 1+1/2 pages... H*ll, the include file is longer than that! My question is: how does a session manager (i.e. "shl") receive the SWTCH hot-key from the tty driver? A quick glance through signal.h/sxt.h/termio.h reveals nothing. Does it just do a read on the controlling channel which blocks until SWTCH? In this particular case, c_cc[VSWTCH] has been reset to '\0' (I believe) so the application can use ^Z for something else.... This makes it totally impossible to switch to another layer. Please, no flames about SysV job control (what job control?)... I'm stuck with it... Thanks! -- Erik Murrey /| // /~~~~/ | / MPX Data Systems, Inc. / | / / /____/ |/ erik@mpx2.UUCP / / / / /| Data Systems, Inc. {spl1,vu-vlsi,bpa}!mpx1!erik / / / / |====================