Re: Win32::API::Struct and GetCursorInfo with PCURSORINFO

Win32::API::Struct->sizeof() seems not to compute correctly struct size when nesting them:

use strict;
use warnings;

use Win32::API;

Win32::API::Struct->typedef('POINT', qw(
  LONG x;
  LONG y;
));

my $Point = Win32::API::Struct->new('POINT'); 
print "sizeof('POINT') = " . $Point->sizeof() . "\n";

Win32::API::Struct->typedef('CURSORINFO', qw(
  DWORD cbSize;
  DWORD flags;
  HANDLE hCursor;
  POINT ptScreenPos;
));

my $CursorInfo = Win32::API::Struct->new('CURSORINFO'); 
print "sizeof('CURSORINFO') = " . $CursorInfo->sizeof() . "\n";

Win32::API::Struct->typedef('MYSTRUCT', qw(
  DWORD cbSize;
  DWORD flags;
  HANDLE hCursor;
));

my $Struct = Win32::API::Struct->new('MYSTRUCT'); 
print "sizeof('MYSTRUCT') = " . $Struct->sizeof() . "\n";

__DATA__
sizeof('POINT') = 8
sizeof('CURSORINFO') = 16
sizeof('MYSTRUCT') = 12
[download]

8 + 12 != 16

Update: investigating a bit more, the problem seems linked with structure member alignment computations used in sizeof method (and require more knowledge than I've available for now :-)).

Bug discovered in v0.40 of Win32::API::Struct and reported as bug#6757 "Win32::API::Struct->sizeof() seems not to compute correctly struct size when nesting them".

____
HTH, Dominique
My two favorites:
If the only tool you have is a hammer, you will see every problem as a nail. --Abraham Maslow
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Comment on Re: Win32::API::Struct and GetCursorInfo with PCURSORINFO Download Code

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Re^2: Win32::API::Struct and GetCursorInfo with PCURSORINFO by bulk88 (Priest) on Oct 19, 2012 at 08:51 UTC
cross posted from CPAN RT Running the code on perlmonks in 0.72 I got `sizeof('POINT') = 8 sizeof('CURSORINFO') = 20 sizeof('MYSTRUCT') = 12` [download] on perlmonks you said you got `sizeof('POINT') = 8 sizeof('CURSORINFO') = 16 sizeof('MYSTRUCT') = 12` [download] `DWORD cbSize; 4 DWORD flags; 4 HANDLE hCursor; 4 POINT ptScreenPos; -> LONG x; 4 LONG y; 4 = 20` [download] So I believe this has been already fixed so I am closing this bug.	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^2: Win32::API::Struct and GetCursorInfo with PCURSORINFO
by bulk88 (Priest) on Oct 19, 2012 at 08:51 UTC

sizeof('POINT') = 8
sizeof('CURSORINFO') = 20
sizeof('MYSTRUCT') = 12
[download]

sizeof('POINT') = 8
sizeof('CURSORINFO') = 16
sizeof('MYSTRUCT') = 12
[download]

  DWORD cbSize; 4
  DWORD flags; 4
  HANDLE hCursor; 4
  POINT ptScreenPos; ->
      LONG x; 4
      LONG y; 4
= 20
[download]

[reply]
[d/l]
[select]