You can use the ExitWindowsEx function to shut down the system. Shutting down flushes file buffers to disk and brings the system to a condition in which it is safe to turn off the computer.
The following example enables the SE_SHUTDOWN_NAME privilege and then shuts down the system.
BOOL MySystemShutdown()
{
HANDLE hToken;
TOKEN_PRIVILEGES tkp;
// Get a token for this process.
if (!OpenProcessToken(GetCurrentProcess(),
TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken))
return( FALSE );
// Get the LUID for the shutdown privilege.
LookupPrivilegeValue(NULL, SE_SHUTDOWN_NAME,
&tkp.Privileges[0].Luid);
tkp.PrivilegeCount = 1; // one privilege to set
tkp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
// Get the shutdown privilege for this process.
AdjustTokenPrivileges(hToken, FALSE, &tkp, 0,
(PTOKEN_PRIVILEGES)NULL, 0);
if (GetLastError() != ERROR_SUCCESS)
return FALSE;
// Shut down the system and force all applications to close.
if (!ExitWindowsEx(EWX_SHUTDOWN | EWX_FORCE, 0))
return FALSE;
return TRUE;
}
For more information about setting security privileges, see Privileges.