Proposal: More portable way to support 64bit platforms

Proposal: More portable way to support 64bit platforms

Short description:

Current PostgreSQL implementation has some portability issues to
support 64bit platforms: pointer calculations using long is not
portable, for example on Windows x64 platform. We propose to use
intptr_t instead of long, which appears in in C99.

Details: intptr_t is defined in <stdint.h>. configure script already
has HAVE_STDINT_H but never uses it. This needs to be enabled.

Please note that Windows/VC++ defines intptr_t in <crtdefs.h>.

Included is a conceptual patch to use intptr_t. Comments are welcome.

Some notes for the patches:

access/common/heaptuple.c:
Casting using (long) is removed. It is no more necessary if we
introduce intptr_t.

include/c.h:
Many Alignment macros which use "long" are rewritten to use intrptr_t.

The patches is against PostgreSQL 8.4beta2. Regression test
passed. Windows x64 is ok even with shared_buffers = 3000MB.

Tested platforms are as follows:

Windows Server 2008 SP1 x64 + Visual Studio 2005
RHEL 4 x86_64 + gcc 3.4.6
FreeBSD 7.1 i386 + gcc 4.2.1

TODO:
Some problems may occur on older platforms, which do not have
stdint.h. In this case we need to add something like below to
include/port/*.h.

/* LP64, IPL64, ILP32, LP32 */
typedef long intptr_t;
typedef unsigned long uintptr_t;

/* LLP64 */
typedef long long intptr_t;
typedef unsigned long long uintptr_t;

Thanks,

--
Tsutomu Yamada // tsutomu(at)sraoss(dot)co(dot)jp
SRA OSS, Inc. Japan