The Win32::API::Struct v0.41 module documentation states the following:

Also note that typedef automatically defines an 'LPNAME' type, which holds a pointer to your structure.

Using the example in that documentation, I have created a POINT structure. This should mean that I have also automatically created an LPPOINT structure.

If this is the case, why does the following not work:

#!c:\perl\bin\perl -w

use strict;
use Data::Dumper;
use Win32::API;

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

my $point = Win32::API::Struct->new( 'LPPOINT' ) or die $!;

print Dumper( $point );

with the error message being:

Unknown Win32::API::Struct 'LPPOINT' at C:\point.pl line 9
Died at C:\point.pl line 9,  line 164.

Is the documentation wrong or am I not reading it correctly?

Thanks,

Re: Win32::API::Struct - Automatic pointer creation not working ?

BrowserUk

created: 2004-07-02 11:33:03

perlmonks

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prlmnks

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LPPOINT is not a structure, it is a type.

POINT is a structure, and LPPOINT is, long pointer to a POINT structure.

You create a POINT structure, fill in the values, and then pass it to an api call that takes an LPPOINT as an argument. Under the covers, Win32::API obtains the address of the memory Perl allocates to hold the POINT structure and passes that to the api.

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Re^2: Win32::API::Struct - Automatic pointer creation not working ?

fx

created: 2004-07-05 05:51:54

perlmonks

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prlmnks

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I've had a look at the C function I am trying to call and althought it wants a pointer to struct, the variable name for this pointer to struct does not being LP - it's just called WORKITEMINFO.

In my mind, therefore, the automatic pointer creation of Win32::API::Struct isn't going to help me.

Does anyone have any suggestions as to how I should progress this - it's almost getting to the point where I might as well just write this in C! :)

fx, Infinity is Colourless