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- /*-------------------------------------------------------------------------
- *
- * dsm.h
- * manage dynamic shared memory segments
- *
- * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
- * Portions Copyright (c) 1994, Regents of the University of California
- *
- * src/include/storage/dsm.h
- *
- *-------------------------------------------------------------------------
- */
- #ifndef DSM_H
- #define DSM_H
-
- #include "storage/dsm_impl.h"
-
- typedef struct dsm_segment dsm_segment;
-
- #define DSM_CREATE_NULL_IF_MAXSEGMENTS 0x0001
-
- /* A sentinel value for an invalid DSM handle. */
- #define DSM_HANDLE_INVALID 0
-
- /* Startup and shutdown functions. */
- struct PGShmemHeader; /* avoid including pg_shmem.h */
- extern void dsm_cleanup_using_control_segment(dsm_handle old_control_handle);
- extern void dsm_postmaster_startup(struct PGShmemHeader *);
- extern void dsm_backend_shutdown(void);
- extern void dsm_detach_all(void);
-
- #ifdef EXEC_BACKEND
- extern void dsm_set_control_handle(dsm_handle h);
- #endif
-
- /* Functions that create or remove mappings. */
- extern dsm_segment *dsm_create(Size size, int flags);
- extern dsm_segment *dsm_attach(dsm_handle h);
- extern void dsm_detach(dsm_segment *seg);
-
- /* Resource management functions. */
- extern void dsm_pin_mapping(dsm_segment *seg);
- extern void dsm_unpin_mapping(dsm_segment *seg);
- extern void dsm_pin_segment(dsm_segment *seg);
- extern void dsm_unpin_segment(dsm_handle h);
- extern dsm_segment *dsm_find_mapping(dsm_handle h);
-
- /* Informational functions. */
- extern void *dsm_segment_address(dsm_segment *seg);
- extern Size dsm_segment_map_length(dsm_segment *seg);
- extern dsm_handle dsm_segment_handle(dsm_segment *seg);
-
- /* Cleanup hooks. */
- typedef void (*on_dsm_detach_callback) (dsm_segment *, Datum arg);
- extern void on_dsm_detach(dsm_segment *seg,
- on_dsm_detach_callback function, Datum arg);
- extern void cancel_on_dsm_detach(dsm_segment *seg,
- on_dsm_detach_callback function, Datum arg);
- extern void reset_on_dsm_detach(void);
-
- #endif /* DSM_H */
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