init

db_include/storage/dsm.h

@@ -0,0 +1,64 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm.h
+ *	  manage dynamic shared memory segments
+ *
+ * Portions Copyright (c) 1996-2021, 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);
+
+extern size_t dsm_estimate_size(void);
+extern void dsm_shmem_init(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 */