Re: Mutex/Lock

From:

"Chris Thomasson" <cristom@comcast.net>

Newsgroups:

comp.lang.c++

Date:

Sat, 31 May 2008 19:54:50 -0700

Message-ID:

<0rSdndX49K7Ukt_VnZ2dnUVZ_jGdnZ2d@comcast.com>

"Gianni Mariani" <gi4nospam@mariani.ws> wrote in message
news:48420b5b$1@news.mel.dft.com.au...

Chris Thomasson wrote:
...

How do you report locking errors? Do you just call `std::unexpected()' or
`std::abort()'? For instance, on Windows, how do you handle
`WAIT_ABANDONED'? Or when `pthread_mutex_lock()' returns `EINVAL' due to
a priority violation?

Abort.
http://austria.svn.sourceforge.net/viewvc/austria/src/austria/posix/code/at_posix_thread_cpp.i?revision=1&view=markup#l_371

I consider it a serious programming error.

Fair enough. However, `WAIT_ABANDONED' can be a legitimate error to receive
on lock acquisition. How do you handle that scenario? I am not sure that
throwing would be the best solution. Perhaps something like this would be
better:

class process_wide_mutex {
  HANDLE m_mtx;

public:
  typedef void (fp_recover_type) ();

  void lock(fp_recover_type* const fp_recover = NULL) {
    DWORD CONST status = WaitForSingleObject(m_mtx, INFINITE);
    if (status != WAIT_OBJECT_0) {
      if (status != WAIT_ABANDONED || ! fp_recover) {
        assert(false);
        std::unexpected();
      }
      fp_recover();
    }
  }

  [...];
};

What do you think?