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Date:      Fri, 7 May 1999 21:26:46 +0100 (BST)
From:      Doug Rabson <dfr@nlsystems.com>
To:        Matthew Dillon <dillon@apollo.backplane.com>
Cc:        current@FreeBSD.ORG
Subject:   Re: Debugging FreeBSD user threads with gdb
Message-ID:  <Pine.BSF.4.05.9905072123330.10400-100000@herring.nlsystems.com>
In-Reply-To: <199905072010.NAA46817@apollo.backplane.com>

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On Fri, 7 May 1999, Matthew Dillon wrote:

> :--- uthread_create.c	1999/03/23 05:07:55	1.12
> :+++ uthread_create.c	1999/05/06 15:27:33
> :@@ -42,6 +42,8 @@
> : #include "pthread_private.h"
> : #include "libc_private.h"
> : 
> :+static int next_tid = 1;
> :+
> : int
> : pthread_create(pthread_t * thread, const pthread_attr_t * attr,
> : 	       void *(*start_routine) (void *), void *arg)
> :@@ -87,6 +89,7 @@
> : 		} else {
> : 			/* Initialise the thread structure: */
> : 			memset(new_thread, 0, sizeof(struct pthread));
> :+			new_thread->tid = next_tid++;
> :
> :Doug Rabson				Mail:  dfr@nlsystems.com
> :Nonlinear Systems Ltd.			Phone: +44 181 442 9037
> 
>     Hmmm.   tid is only an int and some programs which create and destroy
>     threads a lot are almost certainly going to overflow it.  4 billion
>     is not hard to reach.  This can result in duplicate tid's.

Didn't think of that.  It gets a bit ugly inside gdb since gdb needs a
single int to encode the pid and thread id.  I'm currently allowing 20
bits for the pid and 11 for the tid. Any ideas?

--
Doug Rabson				Mail:  dfr@nlsystems.com
Nonlinear Systems Ltd.			Phone: +44 181 442 9037




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