1 files changed, 44 insertions, 0 deletions
diff --git a/src/include/storage/pg_shmem.h b/src/include/storage/pg_shmem.h
new file mode 100644
index 00000000000..fa35e63f725
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+++ b/src/include/storage/pg_shmem.h
@@ -0,0 +1,44 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_shmem.h
+ *	  Platform-independent API for shared memory support.
+ *
+ * Every port is expected to support shared memory with approximately
+ * SysV-ish semantics; in particular, a memory block is not anonymous
+ * but has an ID, and we must be able to tell whether there are any
+ * remaining processes attached to a block of a specified ID.
+ *
+ * To simplify life for the SysV implementation, the ID is assumed to
+ * consist of two unsigned long values (these are key and ID in SysV
+ * terms).  Other platforms may ignore the second value if they need
+ * only one ID number.
+ *
+ *
+ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * $Id: pg_shmem.h,v 1.1 2002/05/05 00:03:29 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PG_SHMEM_H
+#define PG_SHMEM_H
+
+#include <sys/types.h>
+
+
+typedef struct PGShmemHeader	/* standard header for all Postgres shmem */
+{
+	int32		magic;			/* magic # to identify Postgres segments */
+#define PGShmemMagic  679834892
+	pid_t		creatorPID;		/* PID of creating process */
+	uint32		totalsize;		/* total size of segment */
+	uint32		freeoffset;		/* offset to first free space */
+} PGShmemHeader;
+
+
+extern PGShmemHeader *PGSharedMemoryCreate(uint32 size, bool makePrivate,
+										   int port);
+extern bool PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2);
+
+#endif   /* PG_SHMEM_H */