Stuck trying to use Win32::API

newbieperlperson has asked for the wisdom of the Perl Monks concerning the following question:

I am trying to use Win32::API to access advapi32.dll CredRead API, I have little experience with how to interact with Windows DLL’s, pointers, etc and way out of my depth here.

The error I am getting is “Win32::API a function was called with the wrong prototype and caused a C stack inconsistency”, code is below.

The CredRead is used to access the Windows version of Keepass, it is the Windows Credentials Manager.

Here is the code I have, can someone please assist me. Thank You

use strict;
use Win32;
use Win32::API;

#  public enum CRED_TYPE : int 
#    { 
#        GENERIC = 1,
#        DOMAIN_PASSWORD = 2,
#        DOMAIN_CERTIFICATE = 3,
#        DOMAIN_VISIBLE_PASSWORD = 4,
#        MAXIMUM = 5
#    }


my $CredRead = new Win32::API('advapi32.dll', 'CredRead', [qw(P P)],
   'N') or die "Find CredRead: $^E";
   
my $strTarget = "testUser";
#I created user testUser via Control Panel > Credential Manager

$CredRead->Call($strTarget,1) or die "CredRead->Call: $^E";
[download]

Reference URL's:-
https://msdn.microsoft.com/en-us/library/windows/desktop/aa374804(v=vs.85).aspx
http://www.pinvoke.net/default.aspx/advapi32/CredRead%20.html
http://stackoverflow.com/questions/32548714/how-to-store-and-retrieve-credentials-on-windows-using-c-sharp?rq=1

Comment on Stuck trying to use Win32::API Download Code

Replies are listed 'Best First'.
Re: Stuck trying to use Win32::API by runrig (Abbot) on Aug 30, 2016 at 22:23 UTC
It's been a while since I've used Win32::API, but from your link on the CredRead function, I believe the argument prototype should be `[qw(P I I S)]`, not `[qw(P P)]`. then you'll need to pre-allocate the size of the structure returned in the last argument, which you can try to do with Win32::API::Struct (read the Win32::API docs), so that you'll have a convenient object to peek into the structure with.	[reply] [d/l] [select]
Re^2: Stuck trying to use Win32::API by newbieperlperson (Acolyte) on Aug 30, 2016 at 22:42 UTC
Thanks, I think this is currently beyond me, I do not have the domain knowledge to succeed here, is there any other way to do this, perhaps a wrapper?, etc.	[reply]


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