> POSIX is just an API; it doesn't tell you how to design a
> kernel. Generally Linux directly implements POSIX features because
> that is simpler, but for POSIX threads it's worth stepping back and
> asking what it really needs from the kernel. My opinion is that doesn't
> include pid sharing and tids.
>
> David Wragg
It is my understanding that signals cannot be guaranteed to work
according to the POSIX threads specification without the CLONE_PID option.
Please don't say this can be done reliably in userspace; it takes a severe
performance hit for signal handling and adds several levels of complexity
to any pthreads library that uses clone. The way I understand it (and it
has been a while since I read anything on the subject) is that certain
fatal signals are supposed to be received by all threads/affect all
threads no matter which thread receives it. I believe this includes at
least one signal that cannot be handled. So how do you propogate this
signal reliably to all other threads in the process?
Of course, I may have no idea what I'm talking about, too.
William Astle
"Floppity, floppity, flip / The mouse on the mobius strip; / The strip
revolved, / The mouse disolved / In a chronodimensional skip."
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GCS/M/S d- s+:+ !a C++ UL++++$ P++ L+++ !E W++ !N w--- !O !M PS PE V-- Y+
PGP t+@ 5++ X !R tv+@ b+++@ !DI D? G e++ h+ y?
------END GEEK CODE BLOCK------
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