async.h

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/*-------------------------------------------------------------------------
 *
 * async.h
 *    Asynchronous notification: NOTIFY, LISTEN, UNLISTEN
 *
 * Portions Copyright (c) 1996-2026, 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>
 
extern PGDLLIMPORT bool Trace_notify;
extern PGDLLIMPORT int max_notify_queue_pages;
extern PGDLLIMPORT 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 AtSubCommit_Notify(void);
extern void AtSubAbort_Notify(void);
extern void AtPrepare_Notify(void);
 
/* signal handler for inbound notifies (PROCSIG_NOTIFY_INTERRUPT) */
extern void HandleNotifyInterrupt(void);
 
/* process interrupts */
extern void ProcessNotifyInterrupt(bool flush);
 
/* freeze old transaction IDs in notify queue (called by VACUUM) */
extern void AsyncNotifyFreezeXids(TransactionId newFrozenXid);
 
#endif                          /* ASYNC_H */