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3691edfab9
We want to support a "noreturn" decoration on more compilers besides
just GCC-compatible ones, but for that we need to move the decoration
in front of the function declaration instead of either behind it or
wherever, which is the current style afforded by GCC-style attributes.
Also rename the macro to "pg_noreturn" to be similar to the C11
standard "noreturn".
pg_noreturn is now supported on all compilers that support C11 (using
_Noreturn), as well as GCC-compatible ones (using __attribute__, as
before), as well as MSVC (using __declspec). (When PostgreSQL
requires C11, the latter two variants can be dropped.)
Now, all supported compilers effectively support pg_noreturn, so the
extra code for !HAVE_PG_ATTRIBUTE_NORETURN can be dropped.
This also fixes a possible problem if third-party code includes
stdnoreturn.h, because then the current definition of
#define pg_attribute_noreturn() __attribute__((noreturn))
would cause an error.
Note that the C standard does not support a noreturn attribute on
function pointer types. So we have to drop these here. There are
only two instances at this time, so it's not a big loss. In one case,
we can make up for it by adding the pg_noreturn to a wrapper function
and adding a pg_unreachable(), in the other case, the latter was
already done before.
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/pxr5b3z7jmkpenssra5zroxi7qzzp6eswuggokw64axmdixpnk@zbwxuq7gbbcw
88 lines
2.9 KiB
C
88 lines
2.9 KiB
C
/*-------------------------------------------------------------------------
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*
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* ipc.h
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* POSTGRES inter-process communication definitions.
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*
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* This file is misnamed, as it no longer has much of anything directly
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* to do with IPC. The functionality here is concerned with managing
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* exit-time cleanup for either a postmaster or a backend.
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*
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*
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* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/storage/ipc.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef IPC_H
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#define IPC_H
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typedef void (*pg_on_exit_callback) (int code, Datum arg);
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typedef void (*shmem_startup_hook_type) (void);
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/*----------
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* API for handling cleanup that must occur during either ereport(ERROR)
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* or ereport(FATAL) exits from a block of code. (Typical examples are
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* undoing transient changes to shared-memory state.)
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*
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* PG_ENSURE_ERROR_CLEANUP(cleanup_function, arg);
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* {
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* ... code that might throw ereport(ERROR) or ereport(FATAL) ...
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* }
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* PG_END_ENSURE_ERROR_CLEANUP(cleanup_function, arg);
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*
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* where the cleanup code is in a function declared per pg_on_exit_callback.
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* The Datum value "arg" can carry any information the cleanup function
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* needs.
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*
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* This construct ensures that cleanup_function() will be called during
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* either ERROR or FATAL exits. It will not be called on successful
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* exit from the controlled code. (If you want it to happen then too,
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* call the function yourself from just after the construct.)
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*
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* Note: the macro arguments are multiply evaluated, so avoid side-effects.
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*----------
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*/
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#define PG_ENSURE_ERROR_CLEANUP(cleanup_function, arg) \
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do { \
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before_shmem_exit(cleanup_function, arg); \
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PG_TRY()
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#define PG_END_ENSURE_ERROR_CLEANUP(cleanup_function, arg) \
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cancel_before_shmem_exit(cleanup_function, arg); \
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PG_CATCH(); \
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{ \
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cancel_before_shmem_exit(cleanup_function, arg); \
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cleanup_function (0, arg); \
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PG_RE_THROW(); \
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} \
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PG_END_TRY(); \
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} while (0)
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/* ipc.c */
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extern PGDLLIMPORT bool proc_exit_inprogress;
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extern PGDLLIMPORT bool shmem_exit_inprogress;
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pg_noreturn extern void proc_exit(int code);
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extern void shmem_exit(int code);
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extern void on_proc_exit(pg_on_exit_callback function, Datum arg);
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extern void on_shmem_exit(pg_on_exit_callback function, Datum arg);
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extern void before_shmem_exit(pg_on_exit_callback function, Datum arg);
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extern void cancel_before_shmem_exit(pg_on_exit_callback function, Datum arg);
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extern void on_exit_reset(void);
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extern void check_on_shmem_exit_lists_are_empty(void);
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/* ipci.c */
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extern PGDLLIMPORT shmem_startup_hook_type shmem_startup_hook;
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extern Size CalculateShmemSize(int *num_semaphores);
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extern void CreateSharedMemoryAndSemaphores(void);
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#ifdef EXEC_BACKEND
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extern void AttachSharedMemoryStructs(void);
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#endif
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extern void InitializeShmemGUCs(void);
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#endif /* IPC_H */
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