Thanks,
I thought I tried that before, but I may have had some other
error at the time throwing me off the track.
This works:
(define net-wksta-get-info
(get-ffi-obj "NetWkstaGetInfo" netapi-lib
(_fun [_int = 0] [_int = 100] [rets : (_ptr o
_wksta-info-100-pointer)]
-> [ret : _int]
-> (if (zero? ret) ; 0x0 = NERR_Success
rets
(display "fail")))))
(wksta-info-100-platform_id (net-wksta-get-info))
-----Original Message-----
From: John Clements [mailto:[email protected]]
Sent: Tuesday, November 16, 2010 12:24 PM
To: Altenburg, Robert
Cc: users Users
Subject: Re: [racket] ffi: handling return values in arguments?
On Nov 16, 2010, at 9:09 AM, Altenburg, Robert wrote:
> This is probably a simple question, but I can't seem
> to make this work:
>
> The Windows SDK defines the following function:
>
> NET_API_STATUS NetWkstaGetInfo(
> __in LPWSTR servername,
> __in DWORD level,
> __out LPBYTE *bufptr
> );
>
> In this case "bufptr" points to a structure allocated by
> the system that contains the results.
>
> How does one indicate this to get-ffi-obj, and get the returned value
> from the buffer?
I could be wrong, but it looks like this is a standard use of the "o" style
parameter; the ffi interface will allocate it for you at call time, and you can
retrieve the contents after the call returns.
Apologies if I'm misunderstanding your request.
John
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