text: /*-------------------------------------------------------------------------
   *
   * async.h
   *	  Asynchronous notification: NOTIFY, LISTEN, UNLISTEN
   *
   * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   * src/include/commands/async.h
   *
   *-------------------------------------------------------------------------
   */
  #ifndef ASYNC_H
  #define ASYNC_H
  
  #include <signal.h>
  
  #include "fmgr.h"
  
  /*
   * The number of SLRU page buffers we use for the notification queue.
   */
  #define NUM_ASYNC_BUFFERS	8
  
  extern bool Trace_notify;
  extern volatile sig_atomic_t notifyInterruptPending;
  
  extern Size AsyncShmemSize(void);
  extern void AsyncShmemInit(void);
  
  extern void NotifyMyFrontEnd(const char *channel,
  				 const char *payload,
  				 int32 srcPid);
  
  /* notify-related SQL statements */
  extern void Async_Notify(const char *channel, const char *payload);
  extern void Async_Listen(const char *channel);
  extern void Async_Unlisten(const char *channel);
  extern void Async_UnlistenAll(void);
  
  /* perform (or cancel) outbound notify processing at transaction commit */
  extern void PreCommit_Notify(void);
  extern void AtCommit_Notify(void);
  extern void AtAbort_Notify(void);
  extern void AtSubStart_Notify(void);
  extern void AtSubCommit_Notify(void);
  extern void AtSubAbort_Notify(void);
  extern void AtPrepare_Notify(void);
  extern void ProcessCompletedNotifies(void);
  
  /* signal handler for inbound notifies (PROCSIG_NOTIFY_INTERRUPT) */
  extern void HandleNotifyInterrupt(void);
  
  /* process interrupts */
  extern void ProcessNotifyInterrupt(void);
  
  #endif   /* ASYNC_H */
  