[issue3147] tests for sys.getsizeof fail on win64

[Robert Schuppenies]

Robert Schuppenies <okkotonushi at googlemail.com> added the comment:

The tests still do not pass on the AMD64 W2k8. Surprisingly,
struct.calcsize behaves as expected, but sizeof() on the C level does
not. The former seems to assumes long to be 4 byte in size, the latter
8!

The tests pass until it comes to a situation where the size of long
affects the alignment of the structure end. In this case long and
function.
long's structure is 'lP PP l H' which gives an expected size of

8+8+16+4+2(+2) = 40

At least this how I think it should be and struct.calcsize does,
too. But what seems to be computed is

8+8+16+8+2(+6) = 48.

It appears as if sizeof(long) = 8. The same explanation holds true for
the failure on the function size which is 'lp PP 9l' and
struct.calcsize : 8+8+16+36(+4) = 72
sizeof          : 8+8+16+72     = 104

Now I don't know how I should address this problem. It seems to be
Windows AMD64 specific, but I found a post [1] which indicates that
it's Windows AMD64 on Windows 2K specific. Tests do also fail on the
Win64 XP buildbot, but it gets killed before the verbose output is
generated. I don't have access to such a platform, so I cannot verify
it.

It may also be a problem with struct.calcsize on Win64.

Any suggestions?

[1]
http://www.velocityreviews.com/forums/t491385-different-behavior-of-amd64-compiler-14004031041-on-windows-xp-and-2k.html

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nosy: +loewis

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