[Issue 1828] New: Several Thread Issues

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=1828

           Summary: Several Thread Issues
           Product: D
           Version: 2.010
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Keywords: patch
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: kinaba at is.s.u-tokyo.ac.jp


// Credit goes to http://pc11.2ch.net/test/read.cgi/tech/1202623572/30-35n

There are several problems in std.thread.
Please find attached the patch to fix all of them.

1. Thread.start
> state = TS.RUNNING;
> hdl = _beginthreadex(null, cast(uint)stacksize, &threadstart, cast(void*)this, 0, &id);
  If context-switch occurs between these two lines,
  thread which acutually is not running is treated as TS.RUNNING.
  This causes problems, for example in pauseAll().
  So these lines should be property synchronized.

> if (hdl == cast(thread_hdl)0)
  When _beginthreadex fails and this branch is taken,
  the variable nthread should be decremented.

2. std.wait timeouts
  When a call to wait() timeouts (not fails),
  > dw = WaitForSingleObject(hdl, 0xFFFFFFFF);
  > state = TS.FINISHED;
  the current implemetation treats it as it fails.
  But in this case, the thread is indeed still alive and may wake up again
  just after the "state = TS.FINISHED" statement. If that happens,
  pauseAll() do not stop the thread (because it's TS.FINISHED) and
  multiple threads may unintendedly run parallel.
  This IS a problem for std.gc, which is relying on the assumption that
  pauseAll() stops all but gc threads.

3. Priority
  It is convenient if one can set the NORMAL thread priority.


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