Re: NativeCall C++ structure question
On 11/21/22 05:01, ToddAndMargo via perl6-users wrote:
Hi All,
Windows ChromeBook Edition (W11-22H2).
I have been doing a lot of head scratching here.
I have a project were I need to use
BOOL WTSEnumerateSessionsA(
[in] HANDLE hServer,
# WTS_CURRENT_SERVER_HANDLE to use the RD Session Host server that
hosts your application.
[in] DWORD Reserved,
[in] DWORD Version,
[out] PWTS_SESSION_INFOA *ppSessionInfo,
[out] DWORD *pCount
);
to dig out a pointer (*ppSessionInfo) to a
C++ OOP data structure, which is repeated
pCount times. (No problem coding the above.)
The data structure is
C++
typedef struct _WTS_SESSION_INFOA {
DWORD SessionId; # 4 bytes
LPSTR pWinStationName; # 4 or 8 or 12 bytes
WTS_CONNECTSTATE_CLASS State; # 4 or 8 bytes maybe
} WTS_SESSION_INFOA, *PWTS_SESSION_INFOA;
"_WTS_SESSION_INFOA" is 12 bytes in x86 and
24 bytes in x64:
int nSize1 = sizeof WTS_SESSION_INFOA;
// 12 in x86, 24 in x64
What I need to do is shown in C++
WTSEnumerateSessionsA(WTS_CURRENT_SERVER, 0, 1, , )
for (DWORD i = 0; i < dwCount; i++)
{
if (pwsi[i].State == WTSActive)
{
dwSession = pwsi[i].SessionId;
break;
}
}
Basically, I need to walk though the C++ structure
looking for State == WTSActive (0), read the
value of SessionId, exit the loop, and return
the value of SessionId.
How in the world do I use NativeCall to read
"_WTS_SESSION_INFOA"'s structure?
I will only be operating in 64 bit, so I take it
I have to create a Buf of 24 bytes. Then
take the buffer apart using little endian.
And the [i] in the C++ code will be me incrementing
*pCount by 24 bytes each successive read.
Is there an easier way to do this?
Many thanks,
-T
I have to do the above becasue the "SessionID"
is reported incorrectly by M$'s other API's
if you are running your program from the Task
Scheduler
Oh and I almost forgot: A H !
Another question:
Is there a way to use the returned pointer and
the pCount to to read the data into a Raku
Buf or similar?
NativeCall C++ structure question
Hi All,
Windows ChromeBook Edition (W11-22H2).
I have been doing a lot of head scratching here.
I have a project were I need to use
BOOL WTSEnumerateSessionsA(
[in] HANDLE hServer,
# WTS_CURRENT_SERVER_HANDLE to use the RD Session Host server that
hosts your application.
[in] DWORD Reserved,
[in] DWORD Version,
[out] PWTS_SESSION_INFOA *ppSessionInfo,
[out] DWORD *pCount
);
to dig out a pointer (*ppSessionInfo) to a
C++ OOP data structure, which is repeated
pCount times. (No problem coding the above.)
The data structure is
C++
typedef struct _WTS_SESSION_INFOA {
DWORDSessionId;# 4 bytes
LPSTRpWinStationName; # 4 or 8 or 12 bytes
WTS_CONNECTSTATE_CLASS State; # 4 or 8 bytes maybe
} WTS_SESSION_INFOA, *PWTS_SESSION_INFOA;
"_WTS_SESSION_INFOA" is 12 bytes in x86 and
24 bytes in x64:
int nSize1 = sizeof WTS_SESSION_INFOA;
// 12 in x86, 24 in x64
What I need to do is shown in C++
WTSEnumerateSessionsA(WTS_CURRENT_SERVER, 0, 1, , )
for (DWORD i = 0; i < dwCount; i++)
{
if (pwsi[i].State == WTSActive)
{
dwSession = pwsi[i].SessionId;
break;
}
}
Basically, I need to walk though the C++ structure
looking for State == WTSActive (0), read the
value of SessionId, exit the loop, and return
the value of SessionId.
How in the world do I use NativeCall to read
"_WTS_SESSION_INFOA"'s structure?
I will only be operating in 64 bit, so I take it
I have to create a Buf of 24 bytes. Then
take the buffer apart using little endian.
And the [i] in the C++ code will be me incrementing
*pCount by 24 bytes each successive read.
Is there an easier way to do this?
Many thanks,
-T
I have to do the above becasue the "SessionID"
is reported incorrectly by M$'s other API's
if you are running your program from the Task
Scheduler
Oh and I almost forgot: A H !
--
~~
Computers are like air conditioners.
They malfunction when you open windows
~~
Re: What is this handle?
On Sat, Nov 19, 2022 at 10:13 PM, ToddAndMargo via perl6-users mailto:perl6-users@perl.org>> wrote: Hi All, Any of you familiar with native call? In the following C++ HANDLE WTSOpenServerA( [in] LPSTR pServerName ); Is HANDLE a DWORD (32 bit integer)? I just noticed I have HANDLE defined in Raku as constant HANDLE = Pointer[void]; I do believe most C++ pointers are 32 bit cardinals (unsigned integers) Many thanks, -T On 11/21/22 04:36, yary wrote: Handle is a pointer and you can treat it as such. A handle is a pointer to another pointer! it has different uses but basically it is a pointer. Most pointers are a memory address of a value like a number or string, a handle is a memory address of a pointer (another address) to one of those. Thank you! I am being forced to learn C++. AAA Interesting that they use the term HANDLE interchangeably with **pXXX (pointer to a pointer pointer).
Re: What is this handle?
Handle is a pointer and you can treat it as such. A handle is a pointer to another pointer! it has different uses but basically it is a pointer. Most pointers are a memory address of a value like a number or string, a handle is a memory address of a pointer (another address) to one of those. On Sat, Nov 19, 2022 at 10:13 PM, ToddAndMargo via perl6-users < perl6-users@perl.org> wrote: > Hi All, > > Any of you familiar with native call? > > In the following > >C++ >HANDLE WTSOpenServerA( > [in] LPSTR pServerName >); > > Is HANDLE a DWORD (32 bit integer)? > > I just noticed I have HANDLE defined in Raku as > > constant HANDLE = Pointer[void]; > > I do believe most C++ pointers are 32 bit > cardinals (unsigned integers) > > Many thanks, > -T > > -- -y
