I'm working with Win32::API against a Win32 dll. My machine is 64 b and I'm using Cygwin. I'm trying to create a struct defined in C as:

typedef struct cRefStr 
{ 
    size_t length;        
    char const* data;   
} cStrRef;
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I've tried to define the following structure with Win32::API::Struct:

Win32::API::Struct->typedef(CSTRREF =>qw{int n; char* buffer});
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The complete perl code is:

# Sub all 
# cTblAtKey -> findInTableByKey
# cTbl -> myTable
# cCell -> myCell
# ctbl_v2 -> myDll

my $aKey = "UserName";
print $aKey."\n";
my $lengthaKey = length($aKey);
print $lengthaKey."\n";
Win32::API::Struct->typedef(CSTRREF =>qw{int n; char* buffer});
my $structParameter = Win32::API::Struct->new('CSTRREF');
$structParameter->{n}=$lengthaKey;
$structParameter->{buffer}=$aKey;
# C function defined as:
# myCell* findInTableByKey(myTable that, struct cRefStr key, unsigned 
+offset);
# with: 
# struct myCell { 
#     unsigned char opaque[10]; 
#};
my $aKeyFunc = Win32::API->new("myDll.dll",'findInTableByKey', 'NSN','
+C','_cdecl');
if(not defined $aKeyFunc)
{
    die "Couldn't load the function findInTableByKey from the dll";
}
$cellPtr = $aKeyFunc->Call($outputTable,$structParameter,0);
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This breaks with a "Segmentation fault (core dumped)" error.

I've managed to use other functions of the same dll against $outputTable (this was the thread) and I know it is a valid parameter. So I've determined that the issue is with the Struct. I'm trying to substitute $structParameter by its low-level version as suggested in the Win32::API doc, this is using something like pack('NC',$size,$aKey).

I've tried to use a simplified example to understand how this would work. The code in the Win32::API doc, to test struct works as expected:

 #### define the structure
    Win32::API::Struct->typedef( POINT => qw{
        LONG x; 
        LONG y; 
    });
    
    #### import an API that uses this structure
    my $getCursor = new Win32::API('user32', 'GetCursorPos','S','N');
    
    #### create a 'POINT' object
    my $pt = Win32::API::Struct->new('POINT');
    
    #### call the function passing our structure object
    $getCursor->Call($pt);
    
    #### and now, access its members
    my ($x, $y) =($pt->{x}, $pt->{y});
    print "The cursor is at: $x, $y\n";
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However the low-level version suggested in the same doc, throws an error: "Can't call method 'Pack' on an undefined value at ./TestStruct.pl line 27". The broken code:

    #### import an API that uses this structure
    my $getCursor = new Win32::API('user32', 'GetCursorPos','S','N');
    
    #### create a 'POINT' object
    $lpPoint=pack('LL',0,0);
    #### call the function passing our structure object
    $getCursor->Call($lpPoint);
    
    #### and now, access its members
    my ($x,$y) = unpack('LL',$pt);
    print "The cursor is at: ".$x.", ".$y."\n";
[download]

Any suggestion?

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