develooper Front page | perl.perl6.users | Postings from November 2022

Re: NativeCall pointer question?

Thread Previous
From:
ToddAndMargo via perl6-users
Date:
November 21, 2022 06:29
Subject:
Re: NativeCall pointer question?
Message ID:
2eeac7ef-3d6f-d42b-59d0-a2128a013c87@zoho.com
>> On Sun, Nov 20, 2022 at 3:48 AM ToddAndMargo via perl6-users 
>> <perl6-users@perl.org <mailto:perl6-users@perl.org>> wrote:
>> 
>>     Hi All,
>> 
>>     In one of my native call, I get returned a
>>     pointer to a DWORD (uint32).
>> 
>>     How do I turn that into the actual value
>>     in the DWORD?
>> 
>>     Many thanks,
>>     -T
>> 

On 11/20/22 16:00, Clifton Wood wrote:
> @ToddAndMargo,
> 
> Two ways:
> 
>   - Use "my CArray[uint32] $p", use $p as your parameter, and access the 
> value as "$p[0]"
> 
> or
> 
> - Use "my Pointer[uint32] $p"  and use "$p.deref"
> 
> My personal preference is the former, as it is the best way to access 
> AND set the actual former value. The latter can only deref. To my 
> knowledge, you cannot set the referenced value of a Pointer type. I do 
> reserve the right to be wrong on this, though.


Thank you!

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Computers are like air conditioners.
They malfunction when you open windows
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Thread Previous


nntp.perl.org: Perl Programming lists via nntp and http.
Comments to Ask Bjørn Hansen at ask@perl.org | Group listing | About