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8ec569479f
Up until now, we've had a policy of only marking certain variables in the PostgreSQL header files with PGDLLIMPORT, but now we've decided to mark them all. This means that extensions running on Windows should no longer operate at a disadvantage as compared to extensions running on Linux: if the variable is present in a header file, it should be accessible. Discussion: http://postgr.es/m/CA+TgmoYanc1_FSfimhgiWSqVyP5KKmh5NP2BWNwDhO8Pg2vGYQ@mail.gmail.com
76 lines
2.2 KiB
C
76 lines
2.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* dsm_impl.h
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* low-level dynamic shared memory primitives
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*
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* Portions Copyright (c) 1996-2022, 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/dsm_impl.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef DSM_IMPL_H
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#define DSM_IMPL_H
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/* Dynamic shared memory implementations. */
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#define DSM_IMPL_POSIX 1
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#define DSM_IMPL_SYSV 2
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#define DSM_IMPL_WINDOWS 3
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#define DSM_IMPL_MMAP 4
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/*
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* Determine which dynamic shared memory implementations will be supported
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* on this platform, and which one will be the default.
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*/
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#ifdef WIN32
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#define USE_DSM_WINDOWS
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#define DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE DSM_IMPL_WINDOWS
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#else
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#ifdef HAVE_SHM_OPEN
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#define USE_DSM_POSIX
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#define DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE DSM_IMPL_POSIX
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#endif
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#define USE_DSM_SYSV
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#ifndef DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE
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#define DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE DSM_IMPL_SYSV
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#endif
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#define USE_DSM_MMAP
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#endif
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/* GUC. */
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extern PGDLLIMPORT int dynamic_shared_memory_type;
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extern PGDLLIMPORT int min_dynamic_shared_memory;
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/*
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* Directory for on-disk state.
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*
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* This is used by all implementations for crash recovery and by the mmap
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* implementation for storage.
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*/
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#define PG_DYNSHMEM_DIR "pg_dynshmem"
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#define PG_DYNSHMEM_MMAP_FILE_PREFIX "mmap."
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/* A "name" for a dynamic shared memory segment. */
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typedef uint32 dsm_handle;
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/* All the shared-memory operations we know about. */
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typedef enum
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{
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DSM_OP_CREATE,
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DSM_OP_ATTACH,
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DSM_OP_DETACH,
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DSM_OP_DESTROY
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} dsm_op;
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/* Create, attach to, detach from, resize, or destroy a segment. */
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extern bool dsm_impl_op(dsm_op op, dsm_handle handle, Size request_size,
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void **impl_private, void **mapped_address, Size *mapped_size,
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int elevel);
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/* Implementation-dependent actions required to keep segment until shutdown. */
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extern void dsm_impl_pin_segment(dsm_handle handle, void *impl_private,
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void **impl_private_pm_handle);
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extern void dsm_impl_unpin_segment(dsm_handle handle, void **impl_private);
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#endif /* DSM_IMPL_H */
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