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/*------------------------------------------------------------------------- * * ipc.h * POSTGRES inter-process communication definitions. * * This file is misnamed, as it no longer has much of anything directly * to do with IPC. The functionality here is concerned with managing * exit-time cleanup for either a postmaster or a backend. * * * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * src/include/storage/ipc.h * *------------------------------------------------------------------------- */ #ifndef IPC_H #define IPC_H typedef void (*pg_on_exit_callback) (int code, Datum arg); typedef void (*shmem_startup_hook_type) (void); /*---------- * API for handling cleanup that must occur during either ereport(ERROR) * or ereport(FATAL) exits from a block of code. (Typical examples are * undoing transient changes to shared-memory state.) * * PG_ENSURE_ERROR_CLEANUP(cleanup_function, arg); * { * ... code that might throw ereport(ERROR) or ereport(FATAL) ... * } * PG_END_ENSURE_ERROR_CLEANUP(cleanup_function, arg); * * where the cleanup code is in a function declared per pg_on_exit_callback. * The Datum value "arg" can carry any information the cleanup function * needs. * * This construct ensures that cleanup_function() will be called during * either ERROR or FATAL exits. It will not be called on successful * exit from the controlled code. (If you want it to happen then too, * call the function yourself from just after the construct.) * * Note: the macro arguments are multiply evaluated, so avoid side-effects. *---------- */ #define PG_ENSURE_ERROR_CLEANUP(cleanup_function, arg) \ do { \ on_shmem_exit(cleanup_function, arg); \ PG_TRY() #define PG_END_ENSURE_ERROR_CLEANUP(cleanup_function, arg) \ cancel_shmem_exit(cleanup_function, arg); \ PG_CATCH(); \ { \ cancel_shmem_exit(cleanup_function, arg); \ cleanup_function (0, arg); \ PG_RE_THROW(); \ } \ PG_END_TRY(); \ } while (0) /* ipc.c */ extern bool proc_exit_inprogress; extern void proc_exit(int code); extern void shmem_exit(int code); extern void on_proc_exit(pg_on_exit_callback function, Datum arg); extern void on_shmem_exit(pg_on_exit_callback function, Datum arg); extern void cancel_shmem_exit(pg_on_exit_callback function, Datum arg); extern void on_exit_reset(void); /* ipci.c */ extern PGDLLIMPORT shmem_startup_hook_type shmem_startup_hook; extern void CreateSharedMemoryAndSemaphores(bool makePrivate, int port); #endif /* IPC_H */