This is a NativeCall question.
I have 8 bytes (little endian) in a CArray
representing a memory address. How do I create a Pointer
out it?
(CArray
and Pointer
are two of NativeCall's C compatible types. Pointer
s are 8 bytes long. Things should line up, but how does one put the pointer address in a CArray
into a Pointer
in a way acceptable to NativeCall?)
Here is an example of using the windows api call WTSEnumerateSessionsA() you mentioned in the comments:
use NativeCall;
constant BYTE := uint8;
constant DWORD := uint32;
constant WTS_CURRENT_SERVER_HANDLE = 0; # Current (local) server
constant LPSTR := Str;
enum WTS_CONNECTSTATE_CLASS (
WTSActive => 0,
WTSConnected =>1,
WTSConnectQuery => 2,
WTSShadow => 3,
WTSDisconnected => 4,
WTSIdle => 5,
WTSListen => 6,
WTSReset => 7,
WTSDown => 8,
WTSInit => 9
);
constant WTS_CONNECTSTATE_CLASS_int := int32;
class WTS_SESSION_INFOA is repr('CStruct') {
has DWORD $.SessionId is rw;
has LPSTR $.pWinStationName is rw;
has WTS_CONNECTSTATE_CLASS_int $.State;
}
sub GetWTSEnumerateSession(
#`{
C++
BOOL WTSEnumerateSessionsA(
[in] HANDLE hServer,
[in] DWORD Reserved,
[in] DWORD Version,
[out] PWTS_SESSION_INFOA *ppSessionInfo,
[out] DWORD *pCount
);
Returns zero if this function fails.
}
DWORD $hServer, # [in] HANDLE
DWORD $Reserved, # [in] always 0
DWORD $Version, # [in] always 1
Pointer[Pointer] $ppSessionInf is rw, # [out] see _WTS_SESSION_INFOA and _WTS_CONNECTSTATE_CLASS;
DWORD $pCount is rw # [out] DWORD
)
is native("Wtsapi32.dll")
is symbol("WTSEnumerateSessionsA")
returns DWORD # If the function fails, the return value is zero.
{ * };
my $hServer = Pointer[void].new();
$hServer = WTS_CURRENT_SERVER_HANDLE; # let windows figure out what current handle is
my $ppSession = Pointer[Pointer].new(); # A pointer to another pointer to an array of WTS_SESSION_INFO
my DWORD $pCount;
my $ret-code = GetWTSEnumerateSession $hServer, 0, 1, $ppSession, $pCount;
say "Return code: " ~ $ret-code;
my $array = nativecast(Pointer[WTS_SESSION_INFOA], $ppSession.deref);
say "Number of session info structs: " ~ $pCount;
for 0..^ $pCount -> $i {
say "{$i} : Session id: " ~ $array[$i].SessionId;
say "{$i} : Station name: " ~ $array[$i].pWinStationName;
say "{$i} : Connection state: " ~ $array[$i].State;
}
Output (windows 11)
Return code: 1
Number of session info structs: 2
0 : Session id: 0
0 : Station name: Services
0 : Connection state: 4
1 : Session id: 1
1 : Station name: Console
1 : Connection state: 0