EVOLUTION-NINJA

Edit File: pg_shmem.h

/*------------------------------------------------------------------------- * * 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) 1996-2012, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * src/include/storage/pg_shmem.h * *------------------------------------------------------------------------- */ #ifndef PG_SHMEM_H #define PG_SHMEM_H typedef struct PGShmemHeader /* standard header for all Postgres shmem */ { int32 magic; /* magic # to identify Postgres segments */ #define PGShmemMagic 679834894 pid_t creatorPID; /* PID of creating process */ Size totalsize; /* total size of segment */ Size freeoffset; /* offset to first free space */ void *index; /* pointer to ShmemIndex table */ #ifndef WIN32 /* Windows doesn't have useful inode#s */ dev_t device; /* device data directory is on */ ino_t inode; /* inode number of data directory */ #endif } PGShmemHeader; #ifdef EXEC_BACKEND #ifndef WIN32 extern unsigned long UsedShmemSegID; #else extern HANDLE UsedShmemSegID; #endif extern void *UsedShmemSegAddr; extern void PGSharedMemoryReAttach(void); extern void PGSharedMemoryNoReAttach(void); #endif extern PGShmemHeader *PGSharedMemoryCreate(Size size, bool makePrivate, int port); extern bool PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2); extern void PGSharedMemoryDetach(void); #endif /* PG_SHMEM_H */