Sorry -- with the obvious error fixed:
$ /usr/bin/clang-4.0 -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement -Wendif-labels
-Wmissing-format-attribute -Wformat-security -fno-strict-aliasing
-fwrapv -Wno-unused-command-line-argument -Wall -c clang-bug.c
clang-bug.c:55:9: warning: taking address of packed member 'ip_blkid'
of class or structure
'ItemPointerData' may result in an unaligned pointer value
[-Waddress-of-packed-member]
return ItemPointerGetBlockNumber(&ip);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
clang-bug.c:49:25: note: expanded from macro 'ItemPointerGetBlockNumber'
BlockIdGetBlockNumber(&(pointer)->ip_blkid) \
~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
clang-bug.c:39:19: note: expanded from macro 'BlockIdGetBlockNumber'
(BlockNumber) (((blockId)->bi_hi << 16) | ((uint16) (blockId)->bi_lo)) \
^~~~~~~
clang-bug.c:55:9: warning: taking address of packed member 'ip_blkid'
of class or structure
'ItemPointerData' may result in an unaligned pointer value
[-Waddress-of-packed-member]
return ItemPointerGetBlockNumber(&ip);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
clang-bug.c:49:25: note: expanded from macro 'ItemPointerGetBlockNumber'
BlockIdGetBlockNumber(&(pointer)->ip_blkid) \
~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
clang-bug.c:39:55: note: expanded from macro 'BlockIdGetBlockNumber'
(BlockNumber) (((blockId)->bi_hi << 16) | ((uint16) (blockId)->bi_lo)) \
^~~~~~~
2 warnings generated.
#if defined(__GNUC__) || defined(__SUNPRO_C) || defined(__IBMC__)
#define pg_attribute_aligned(a) __attribute__((aligned(a)))
#define pg_attribute_packed() __attribute__((packed))
#endif
typedef unsigned BlockNumber;
typedef unsigned short uint16;
typedef uint16 OffsetNumber;
typedef struct BlockIdData
{
uint16 bi_hi;
uint16 bi_lo;
} BlockIdData;
typedef struct ItemPointerData
{
BlockIdData ip_blkid;
OffsetNumber ip_posid;
}
/* If compiler understands packed and aligned pragmas, use those */
#if defined(pg_attribute_packed) && defined(pg_attribute_aligned)
pg_attribute_packed()
pg_attribute_aligned(2)
#endif
ItemPointerData;
typedef ItemPointerData *ItemPointer;
/*
* BlockIdGetBlockNumber
* Retrieve the block number from a block identifier.
*/
#define BlockIdGetBlockNumber(blockId) \
( \
(BlockNumber) (((blockId)->bi_hi << 16) | ((uint16) (blockId)->bi_lo)) \
)
/*
* ItemPointerGetBlockNumber
* Returns the block number of a disk item pointer.
*/
#define ItemPointerGetBlockNumber(pointer) \
( \
BlockIdGetBlockNumber(&(pointer)->ip_blkid) \
)
int main() {
ItemPointerData ip;
return ItemPointerGetBlockNumber(&ip);
}
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
