Re: real POSIX.1b semaphores

David S. Miller (
Mon, 18 Nov 1996 23:54:09 -0500

From: Ulrich Drepper <>
Date: 19 Nov 1996 05:44:58 +0100

OK, and does signal delivery works as expected? I.e., can one
thread send a signal to another in the same process? I don't know
much about this but haven't found a sign of a thread ID.

Hmmm, maybe it does not act as expected. And you are correct that a
thread_id mechanism is not there.

Linus spoke some time ago on this on some linux-kernel thread.
Basically his consensus was that adding a thread_id that was seperate
from the normal pid was asking for trouble and a stupid idea.

He instead postulated an idea of encoding the thread_id within the
pid itself, using the high order bits of the pid value or something
similar. The nice results of this are that nothing breaks, like
/proc/pid etc.

Yow! 10.49 MB/s remote host TCP bandwidth ////
over 100Mb/s ethernet. Beat that! ////
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David S. Miller, /_____________/ / // /_/ ><