Nope. Do you want to make Linux-specific version of all the shells, utilities
etc? "kill" is a built-in in most shells, perl etc..
The good thing about putting the tid in the high bits is that you can use
_unmodified_ generic UNIX utilities that do not know threads from a hole in
the ground. You can write a "perl" script that does thread-aware things (the
perl script _itself_ wouldn't be threaded, but the perl programmer could make
it be the front-end to a threaded program, for example). Or think of a Tcl/Tk
program where the Tcl/Tk scripts are just a front-end to a threaded process..
You want that Tcl/Tk program to signal individual threads (let's say there is
one thread for user interface stuff, for example), but you do NOT want to
modify the Tcl/Tk interpreter itself.
You might use something like "pid.tid" as a _shorthand_ in specific tools
(instead of using a unwieldly 32-bit pid that is hard to remember), but as
it's not generic it should be considered the secondary interface at most.
Linus