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From: Mikael Karpberg <karpen@ocean.campus.luth.se>
Message-Id: <199708250220.EAA25202@ocean.campus.luth.se>
Subject: Re: pthread_join question
In-Reply-To: <Pine.BSF.3.96.970824041223.838A-100000@ns2.harborcom.net> from Bradley Dunn at "Aug 24, 97 04:31:15 am"
To: bradley@dunn.org
Date: Mon, 25 Aug 1997 04:20:22 +0200 (CEST)
Cc: freebsd-hackers@FreeBSD.ORG
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According to Bradley Dunn:
> Hi,
> 
> I just bought _Programming with POSIX Threads_ by Butenhof so I could
> learn a little bit about threads. I have a question about pthread_join in
> FreeBSD. It seems from looking at the source in
> src/lib/libc_r/uthread/uthread_join.c
> and from trying the test code on page 32 in the book that pthread_join
> will always return -1 if an error occurs. The book says that Pthreads
> doesn't use errno and returns the error directly. Can someone help me
> understand this better?
[...]
> If I modify the code so that it checks errno, I find that errno is
> indeed ESRCH (and the source for pthread_join seems to indicate this is
> normal behavior).

>From the only reference I have available (Solaris man page):

RETURN VALUES
     If successful,  both  pthread_join()  and  thr_join()  would
     return 0; otherwise, an error number is returned to indicate
     the error.

Seems like you're right. Then I guess libc_r has a bug. :-)
Try doing a send-pr with the problem. Maybe check the cvs online for the
last few commits, and mail the person that seem to be most responsible for
libc_r and tell him you have done a send-pr, too. :-)

> Oh, and another quick question. I compiled the program using:
> cc -Wall -othread_error thread_error.c -lc_r
> Is the '-lc_r' the correct way to get the thread functions linked in?

I really have no idea, but since no one else seem to have answered..
I think I saw a commit adding -thread or -threads option...
Try:
  cc -Wall -threads -othread_error thread_error.c
or
  cc -Wall -thread -othread_error thread_error.c

And see if it works :-)

> PS -- Please CC me as I am not on -hackers.

Done.

  /Mikael