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/*-------------------------------------------------------------------------
*
* pgmagic.h
* Defines a magic block that can mark a module in a way so show that
* it is compatible with the server it is being loaded into.
*
* This file is intended to be included into modules that wish to load
* themselves into the backend. All they need to do is include this header
* into one of the source files and include the line:
*
* PG_MODULE_MAGIC;
*
* The trailing semi-colon is optional. To work with versions of PostgreSQL
* that do not support this, you may put an #ifdef/endif block around it.
*
* Note, there is space available, particularly in the bitfield part. If it
* turns out that a change has happened within a major release that would
* require all modules to be recompiled, just setting one unused bit there
* will do the trick.
*
* Originally written by Martijn van Oosterhout <kleptog@svana.org>
*
* $PostgreSQL: pgsql/src/include/pgmagic.h,v 1.1 2006/05/30 14:09:32 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef PGMAGIC_H
#define PGMAGIC_H
#include "c.h"
/* The main structure in which the magic is stored. the length field is used
* to detect major changes */
typedef struct {
int len;
int version;
int magic;
} Pg_magic_struct;
/* Declare the module magic function. It needs to be a function as the dlsym
* in the backend is only guarenteed to work on functions, not data */
typedef Pg_magic_struct *(*PGModuleMagicFunction) (void);
#define PG_MAGIC_FUNCTION_NAME Pg_magic_func
#define PG_MAGIC_FUNCTION_NAME_STRING "Pg_magic_func"
#define PG_MODULE_MAGIC \
extern DLLIMPORT Pg_magic_struct *PG_MAGIC_FUNCTION_NAME(void); \
Pg_magic_struct * \
PG_MAGIC_FUNCTION_NAME(void) \
{ \
static Pg_magic_struct Pg_magic_data = PG_MODULE_MAGIC_DATA; \
return &Pg_magic_data; \
}
/* Common user adjustable constants */
#define PG_MODULE_MAGIC_CONST \
((INDEX_MAX_KEYS << 0) + \
(FUNC_MAX_ARGS << 8) + \
(NAMEDATALEN << 16))
/* Finally, the actual data block */
#define PG_MODULE_MAGIC_DATA \
{ \
sizeof(Pg_magic_struct), \
PG_VERSION_NUM / 100, /* Major version of postgres */ \
PG_MODULE_MAGIC_CONST, /* Constants users can configure */ \
}
#endif /* PGMAGIC_H */
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