Linker error

[Null]

Code:

#include <windows.h>
#include <ntdll.h>
int main()
{
SHUTDOWN_ACTION sha;
sha=ShutdownNoReboot;
NtShutdownSystem(sha);

}

when i compile this i get error about undefined reference. What's wrong here?
I'm using Dev-C++ with mingw compiler.

[Hammurabi]

Have you linked to ntdll?

[Null]

I added a parameter to linker: -lntdll

[Hammurabi]

Maybe it's not available on your system?

[Null]

But libntdll.a exist in lib folder

[Hammurabi]

That function isn't documented.
You should use WindowsExitEx().
You have to adjust your privileges first, though, so it's a little bulky.
Here's a chunk of code:

#include <windows.h>
#include <iostream>
#include <string>

BOOL shutDown()
{
    HANDLE hToken;
    TOKEN_PRIVILEGES priv;

    // Adjust privileges
 
    if ( !OpenProcessToken ( GetCurrentProcess(),
         TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken ))
        return FALSE;
    LookupPrivilegeValue ( NULL, SE_SHUTDOWN_NAME,
          &priv.Privileges[0].Luid );
    priv.PrivilegeCount = 1;
    priv.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
    AdjustTokenPrivileges ( hToken, FALSE, &priv, 0,
        (PTOKEN_PRIVILEGES)NULL, 0);
    if ( GetLastError() != ERROR_SUCCESS )
        return FALSE;

    // Shutdown system

    return ExitWindowsEx ( EWX_SHUTDOWN | EWX_FORCE, 0 );
}

int main()
{
    std::string ans;
    std::cout << "Shutdown? ";
    std::getline ( std::cin, ans );
    if ( ans != "yes" ) return 0;
    if ( !shutDown() )
        std::cout << "Can't shut down\n";
}

[Geinbits]

Unless your reasons for making this program were for learning purposes, I think a batch file is a much simpler solution.

cd..
shutdown /s /t 0

ps. You might not need the "cd..", but for some reason on my system if I don't have it in there my computer outputs "shutdown /s /t 0" infinitely and never actually shuts down.

[Null]

But why NtShutdownSystem() doesn't work?

[george135]

NtShutdownSystem() works but you must not call it like that. (dc)
See on adv. Win32 group
(http://groups.google.com/group/comp.os.ms-windows.programmer.win32/topics?lnk=srg)

[Null]

Now i'm totally confused. I decided to access function directly from dll but it doesn't work.

int main()
{
typedef int(__cdecl *MYPROC)(SHUTDOWN_ACTION);
MYPROC h;
SHUTDOWN_ACTION sha;
sha=ShutdownReboot;
HINSTANCE hi;
hi=GetModuleHandle("ntdll.dll");
h=(MYPROC)GetProcAddress(hi,"NtShutdownSystem");
if(h!=NULL) cout <<"success";
(h)(sha); //calling NtShutdownSystem()

}

[z05DSL3A]

Have you got the privileges to call NtShutdownSystem?

NtShutdownSystem is undocumented, but I have found the following that may help:

HANDLE hToken;
if (OpenProcessToken(GetCurrentProcess(), 
TOKEN_QUERY|TOKEN_ADJUST_PRIVILEGES, &hToken))
{
    TOKEN_PRIVILEGES tkp;

    LookupPrivilegeValue(NULL, SE_SHUTDOWN_NAME, &tkp.Privileges[0].Luid);

    tkp.PrivilegeCount = 1;
    tkp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED; 

    AdjustTokenPrivileges(hToken, FALSE, &tkp, 0, NULL, 0);
    CloseHandle(hToken);
}

NtShutdownSystem(ShutdownNoReboot);

[Null]

Thanks Grey Wolf, it worked! And shutdown time is just 1 secod :-)