[svn] * src/lock.h,src/lock.c,src/noffle.c: Add lazy lock release. Only release the lock and close the databases if (a) another process signals us SIGUSR1 indicating it wants the lock, or (b) it is explicitly requested by a call to new function Lock_syncDatabases(). When waiting for the lock, SIGUSR1 the holding process every second. This is all an attempt to minimise the number of times we need to close and open the database. When (ha!) the database is replaced by something that can handle multiple simultaneous writers (with appropriate locking) this won't be necessary.

/*
  control.h

  Control actions needed by server and command line.

  $Id: control.h 51 2000-05-05 23:49:38Z uh1763 $
*/

#ifndef CONTROL_H
#define CONTROL_H

#if HAVE_CONFIG_H
#include <config.h>
#endif

#define	CANCEL_OK		0
#define	CANCEL_NO_SUCH_MSG	1
#define	CANCEL_NEEDS_MSG	2

/*
   Cancel a message. Return CANCEL_OK if completely cancelled,
   CANCEL_NO_SUCH_MSG if no message with that ID exists, and
   CANCEL_NEEDS_MSG if a 'cancel' message should be propagated upstream
   to cancel the message elsewhere.
 */
int
Ctrl_cancel( const char *msgId );

#endif