Mailing-List: contact new-httpd-help@apache.org; run by ezmlm
Precedence: bulk
Reply-To: new-httpd@apache.org
Sender: wmperry@aventail.com
To: new-httpd@apache.org
Subject: condition variables in APR...
From: wmperry@aventail.com (William M. Perry)
Content-Type: text/plain; charset=us-ascii
Date: Wed, 01 Aug 2001 10:02:15 -0500
Message-ID: <868zh3962w.fsf@hel.bp.aventail.com>
Lines: 32
User-Agent: Gnus/5.090004 (Oort Gnus v0.04) XEmacs/21.5 (anise)
MIME-Version: 1.0
Status: O

My boss says it is ok to contribute the cross-platform condition variable
code I wrote here.  It is currently not very APR like though.  It uses
common macros defined in header files with common C code.  I can rip out
the implementation easily into unix & win32 files though.  beos & mac will
have to be done by someone else.  I haven't programmed on a mac in close to
a decade. :)

Where is the best place to put this in APR?  It doesn't seem to belong in
apr/locks/ - does it deserve its own subdirectory in APR?

For win32 this uses events:

init      -- pcond = CreateEvent(NULL,TRUE,TRUE,NULL);
wait      -- HANDLE h[2]; h[0] = pcond; h[1] = mutex;
	     MUTEX_UNLOCK(mid);
	     WaitForMultipleObjects(2,h,TRUE,INFINITE);
signal    -- SetEvent(pcond);
broadcast -- ResetEvent(pcond);
destroy   -- CloseHandle(pcond);

On unix of course we would just use the pthread_cond_xxx routines.  The
only sticky point I see is having some way to get the underlying system
representation from an `apr_lock_t' to pass to WaitForMultipleObjects or
pthread_cond_wait.

Would it be sane to include locks.h and do the appropriate munging?  Nobody
outside of the locks/ directory seems to use it (other that
misc/unix/start.c and that is just for a forward function declaration).

-bp
-- 
Ceterum censeo vi esse delendam