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/*-------------------------------------------------------------------------
*
* waiteventset.h
* ppoll() / pselect() like interface for waiting for events
*
* WaitEventSets allow to wait for latches being set and additional events -
* postmaster dying and socket readiness of several sockets currently - at the
* same time. On many platforms using a long lived event set is more
* efficient than using WaitLatch or WaitLatchOrSocket.
*
* WaitEventSetWait includes a provision for timeouts (which should be avoided
* when possible, as they incur extra overhead) and a provision for postmaster
* child processes to wake up immediately on postmaster death. See
* storage/ipc/waiteventset.c for detailed specifications for the exported
* functions.
*
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/storage/waiteventset.h
*
*-------------------------------------------------------------------------
*/
#ifndef WAITEVENTSET_H
#define WAITEVENTSET_H
#include "utils/resowner.h"
/*
* Bitmasks for events that may wake-up WaitLatch(), WaitLatchOrSocket(), or
* WaitEventSetWait().
*/
#define WL_LATCH_SET (1 << 0)
#define WL_SOCKET_READABLE (1 << 1)
#define WL_SOCKET_WRITEABLE (1 << 2)
#define WL_TIMEOUT (1 << 3) /* not for WaitEventSetWait() */
#define WL_POSTMASTER_DEATH (1 << 4)
#define WL_EXIT_ON_PM_DEATH (1 << 5)
#ifdef WIN32
#define WL_SOCKET_CONNECTED (1 << 6)
#else
/* avoid having to deal with case on platforms not requiring it */
#define WL_SOCKET_CONNECTED WL_SOCKET_WRITEABLE
#endif
#define WL_SOCKET_CLOSED (1 << 7)
#ifdef WIN32
#define WL_SOCKET_ACCEPT (1 << 8)
#else
/* avoid having to deal with case on platforms not requiring it */
#define WL_SOCKET_ACCEPT WL_SOCKET_READABLE
#endif
#define WL_SOCKET_MASK (WL_SOCKET_READABLE | \
WL_SOCKET_WRITEABLE | \
WL_SOCKET_CONNECTED | \
WL_SOCKET_ACCEPT | \
WL_SOCKET_CLOSED)
typedef struct WaitEvent
{
int pos; /* position in the event data structure */
uint32 events; /* triggered events */
pgsocket fd; /* socket fd associated with event */
void *user_data; /* pointer provided in AddWaitEventToSet */
#ifdef WIN32
bool reset; /* Is reset of the event required? */
#endif
} WaitEvent;
/* forward declarations to avoid exposing waiteventset.c implementation details */
typedef struct WaitEventSet WaitEventSet;
typedef struct Latch Latch;
/*
* prototypes for functions in waiteventset.c
*/
extern void InitializeWaitEventSupport(void);
extern WaitEventSet *CreateWaitEventSet(ResourceOwner resowner, int nevents);
extern void FreeWaitEventSet(WaitEventSet *set);
extern void FreeWaitEventSetAfterFork(WaitEventSet *set);
extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
Latch *latch, void *user_data);
extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
extern int WaitEventSetWait(WaitEventSet *set, long timeout,
WaitEvent *occurred_events, int nevents,
uint32 wait_event_info);
extern int GetNumRegisteredWaitEvents(WaitEventSet *set);
extern bool WaitEventSetCanReportClosed(void);
#ifndef WIN32
extern void WakeupMyProc(void);
extern void WakeupOtherProc(int pid);
#endif
#endif /* WAITEVENTSET_H */
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