Date: Fri, 4 Aug 2006 16:06:57 +0200 From: Jeremie Le Hen <jeremie@le-hen.org> To: freebsd-threads@FreeBSD.org Subject: system scope vs. process scope Message-ID: <20060804140657.GK4498@obiwan.tataz.chchile.org>
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Hi, occasionally, I saw environnement variables LIBPTHREAD_SYSTEM_SCOPE and LIBPTHREAD_PROCESS_SCOPE mentionned hither and thither. I grep(1)'ed through the source tree for some documentation, but I wasn't able to find any. Read the source Luke... It seems that the PTHREAD_SCOPE_SYSTEM thread attribute is the default. Intuitivelely, I would say that setting the PTHREAD_SCOPE_PROCESS attribute creates a new process with its address space being shared with the other userland threads (a la Linux) whereas the default behaviour is to create a new kernel thread. Am I right ? What are the pros and cons of either methods ? In libthr, it seems those environnement variables / attributes leads to set a flag THR_SYSTEM_SCOPE which doesn't seem to be used in the library nor in the kernel. OTOH, in libpthread (libkse), it seems to be widely used. I fumbled through the code, but I am not sure to understand what these flags really do. Thank you. -- Jeremie Le Hen < jeremie at le-hen dot org >< ttz at chchile dot org >
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