That pack is definitely wrong. $dwReserved should be simply 8.

The signature is completely wrong 

HRESULT                          -> N or I, not sure
URLDownloadToFile(      
   LPUNKNOWN pCaller,            -> P
   LPCTSTR szURL,                -> P 
   LPCTSTR szFileName,           -> P
   DWORD dwReserved,             -> N
   LPBINDSTATUSCALLBACK lpfnCB   -> P
);

[download]
Win32::API->Import(
   'urlmon', 'URLDownloadToFile', 'PPPNP', 'N',
);

my $pCaller    = 0;
my $szURL      = 'http://somedomain.com/pic.jpg';
my $szFileName = 'c:\1img.jpg';
my $dwReserved = 8;  # Download from offline cache
my $lpfnCB     = 0;

my $res = URLDownloadToFile(
   $pCaller,
   $szURL,
   $szFileName,
   $dwReserved,
   $lpfnCB,
) or die Win32::FormatMessage(Win32::GetLastError);

[download]

If that doesn't work, also make sure the DLL function was compiled using the __stdcall (aka WINAPI) calling convention. Win32::API can't call it properly if it wasn't. 

HRESULT WINAPI URLDownloadToFile(      
   LPUNKNOWN pCaller,
   LPCTSTR szURL,
   LPCTSTR szFileName,
   DWORD dwReserved,
   LPBINDSTATUSCALLBACK lpfnCB
);

[download]

Update: Replaced undef with $pCaller and $lpfnCB.

In reply to Re: Win32::API help by ikegami
in thread Win32::API help by Zukoff

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