Author: sewardj
Date: 2007-11-05 11:02:51 +0000 (Mon, 05 Nov 2007)
New Revision: 7100
Log:
Warn against the perils of detached threads.
Modified:
branches/THRCHECK/thrcheck/docs/tc-manual.xml
Modified: branches/THRCHECK/thrcheck/docs/tc-manual.xml
===================================================================
--- branches/THRCHECK/thrcheck/docs/tc-manual.xml 2007-11-05 10:48:45 UTC
(rev 7099)
+++ branches/THRCHECK/thrcheck/docs/tc-manual.xml 2007-11-05 11:02:51 UTC
(rev 7100)
@@ -1025,6 +1025,29 @@
</listitem>
<listitem>
+ <para>Round up all finished threads using pthread_join. Avoid
+ detaching threads: don't create threads in the detached state, and
+ don't call pthread_detach on existing threads.</para>
+
+ <para>Using pthread_join to round up finished threads provides a
+ clear synchronisation point that both Thrcheck and programmers can
+ see. This synchronisation point allows Thrcheck to adjust its
+ memory ownership
+ models <link linkend="tc-manual.data-races.exclusive">as described
+ extensively above</link>, which helps Thrcheck produce more
+ accurate error reports.</para>
+
+ <para>If you don't call pthread_join on a thread, Thrcheck has no
+ way to know when it finishes, relative to any significant
+ synchronisation points for other threads in the program. So it
+ assumes that the thread lingers indefinitely and can potentially
+ interfere indefinitely with the memory state of the program. It
+ has every right to assume that -- after all, it might really be
+ the case that, for scheduling reasons, the exiting thread did run
+ very slowly in the last stages of its life.</para>
+ </listitem>
+
+ <listitem>
<para>POSIX requires that implementations of standard I/O (printf,
fprintf, fwrite, fread, etc) are thread safe. Unfortunately GNU
libc implements this by using internal locking primitives that
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