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Re: Trivial C11 threads.h wrapper (public domain)

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From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c, comp.programming.threads
Subject Re: Trivial C11 threads.h wrapper (public domain)
Date Mon, 01 Oct 2012 15:19:28 -0700
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Jens Gustedt <jens.gustedt@loria.fr> writes:
[...]
> The problem here is that this is not an interface that I/we design,
> but that this is supposed to emulate a C library interface. The
> description there is extremely concise, and in particular it doesn't
> foresee the possibility of failure of the call. (For other functions
> the standard would have some generic phrase "if you pass invalid input
> to the function the behavior is undefined".)
[...]

I haven't studied C11's <threads.h> closely, but I do find the
description of mtx_destroy() a bit troubling:

    Synopsis

1       #include <threads.h>
        void mtx_destroy(mtx_t *mtx);

    Description

2   The mtx_destroy function releases any resources used by the mutex
    pointed to by mtx. No threads can be blocked waiting for the
    mutex pointed to by mtx.

    Returns

3   The mtx_destroy function returns no value.

So what does mtx_destroy() do if some thread *is* blocked waiting
for mtx?  I suppose the behavior is undefined by omission, but
changing the word "can" to "shall" would have made that explicit.

And why not define the behavior, more or less as POSIX does?
Would detecting blocked threads be too difficult on some systems?

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
    Will write code for food.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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Thread

Trivial C11 threads.h wrapper (public domain) John Tsiombikas <nuclear@member.fsf.org> - 2012-09-27 03:38 +0000
  Re: Trivial C11 threads.h wrapper (public domain) Keith Thompson <kst-u@mib.org> - 2012-09-26 20:50 -0700
    Re: Trivial C11 threads.h wrapper (public domain) John Tsiombikas <nuclear@member.fsf.org> - 2012-09-27 04:15 +0000
      Re: Trivial C11 threads.h wrapper (public domain) Lorenzo Beretta <lory.fulgi@infinito.it> - 2012-09-27 16:35 +0200
        Re: Trivial C11 threads.h wrapper (public domain) John Tsiombikas <nuclear@member.fsf.org> - 2012-09-27 15:58 +0000
          Re: Trivial C11 threads.h wrapper (public domain) Lorenzo Beretta <lory.fulgi@infinito.it> - 2012-09-27 18:27 +0200
          Re: Trivial C11 threads.h wrapper (public domain) William Ahern <william@wilbur.25thandClement.com> - 2012-09-28 12:08 -0700
          Re: Trivial C11 threads.h wrapper (public domain) Kaz Kylheku <kaz@kylheku.com> - 2012-09-28 19:38 +0000
          Re: Trivial C11 threads.h wrapper (public domain) Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-09-28 15:50 -0400
            Re: Trivial C11 threads.h wrapper (public domain) Lorenzo Beretta <lory.fulgi@infinito.it> - 2012-09-29 18:41 +0200
  Re: Trivial C11 threads.h wrapper (public domain) Markus Elfring <Markus.Elfring@web.de> - 2012-09-27 13:45 +0200
    Re: Trivial C11 threads.h wrapper (public domain) John Tsiombikas <nuclear@member.fsf.org> - 2012-09-27 16:14 +0000
      Re: Trivial C11 threads.h wrapper (public domain) Markus Elfring <Markus.Elfring@web.de> - 2012-09-28 12:05 +0200
        Re: Trivial C11 threads.h wrapper (public domain) Keith Thompson <kst-u@mib.org> - 2012-09-28 03:39 -0700
        Re: Trivial C11 threads.h wrapper (public domain) James Kuyper <jameskuyper@verizon.net> - 2012-09-28 08:23 -0400
          Re: Trivial C11 threads.h wrapper (public domain) John Tsiombikas <nuclear@member.fsf.org> - 2012-09-28 19:48 +0000
    Re: Trivial C11 threads.h wrapper (public domain) Toby Douglass <a@b.com> - 2012-10-01 20:19 +0200
      Re: Trivial C11 threads.h wrapper (public domain) James Kuyper <jameskuyper@verizon.net> - 2012-10-01 14:37 -0400
      Re: Trivial C11 threads.h wrapper (public domain) Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-10-01 14:38 -0400
      Re: Trivial C11 threads.h wrapper (public domain) Keith Thompson <kst-u@mib.org> - 2012-10-01 14:58 -0700
  Re: Trivial C11 threads.h wrapper (public domain) Jens Gustedt <jens.gustedt@loria.fr> - 2012-09-28 20:22 +0200
    Re: Trivial C11 threads.h wrapper (public domain) Markus Elfring <Markus.Elfring@web.de> - 2012-09-30 23:13 +0200
      Re: Trivial C11 threads.h wrapper (public domain) Keith Thompson <kst-u@mib.org> - 2012-09-30 14:28 -0700
        Re: Trivial C11 threads.h wrapper (public domain) Jens Gustedt <jens.gustedt@loria.fr> - 2012-10-01 00:37 +0200
          Re: Trivial C11 threads.h wrapper (public domain) Jens Gustedt <jens.gustedt@loria.fr> - 2012-10-01 00:44 +0200
            Re: Trivial C11 threads.h wrapper (public domain) Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-09-30 19:48 -0400
              Re: Trivial C11 threads.h wrapper (public domain) Jens Gustedt <jens.gustedt@loria.fr> - 2012-10-01 08:26 +0200
          Re: Trivial C11 threads.h wrapper (public domain) Markus Elfring <Markus.Elfring@web.de> - 2012-10-01 11:25 +0200
            Re: Trivial C11 threads.h wrapper (public domain) Jens Gustedt <jens.gustedt@loria.fr> - 2012-10-01 11:47 +0200
              Re: Trivial C11 threads.h wrapper (public domain) Markus Elfring <Markus.Elfring@web.de> - 2012-10-01 12:05 +0200
                Re: Trivial C11 threads.h wrapper (public domain) Jens Gustedt <jens.gustedt@loria.fr> - 2012-10-01 13:15 +0200
                Clarification for interface specification "C11 threads.h" Markus Elfring <Markus.Elfring@web.de> - 2012-10-03 11:02 +0200
                Re: Clarification for interface specification "C11 threads.h" Keith Thompson <kst-u@mib.org> - 2012-10-03 13:29 -0700
                Re: Clarification for interface specification "C11 threads.h" Jens Gustedt <jens.gustedt@loria.fr> - 2012-10-04 13:35 +0200
                Re: Clarification for interface specification "C11 threads.h" Markus Elfring <Markus.Elfring@web.de> - 2012-10-12 17:45 +0200
                Re: Trivial C11 threads.h wrapper (public domain) Noob <root@127.0.0.1> - 2012-10-01 18:10 +0200
              Re: Trivial C11 threads.h wrapper (public domain) Nick Bowler <nbowler@draconx.ca> - 2012-10-01 19:28 +0000
              Re: Trivial C11 threads.h wrapper (public domain) Keith Thompson <kst-u@mib.org> - 2012-10-01 15:19 -0700
                Re: Trivial C11 threads.h wrapper (public domain) Kaz Kylheku <kaz@kylheku.com> - 2012-10-01 23:57 +0000
      Re: Trivial C11 threads.h wrapper (public domain) Jens Gustedt <jens.gustedt@loria.fr> - 2012-10-02 14:48 +0200

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