Access violation reading from location in C++ - c++

Question

Why is the last statement throwing Access Violation?
I wanted to write the status of a service into an XML file.
#define STR_SERVICE_STATUS_INPUT__XML_CONTENT _T("<SERVICE NAME = \"%s\" STARTUP_TYPE = \"0x%d\" />\r\n\r\n")
CString csWriteBufferTemp;
DWORD dwBufferSize;
DWORD dwBytesNeeded;
SC_HANDLE schHandle;
LPQUERY_SERVICE_CONFIG st_lpqscServiceInfo;
schHandle = OpenService(IN_schHandle, (CString)cArgentServices[i], SERVICE_QUERY_CONFIG);
bRC = QueryServiceConfig(schHandle, NULL, 0, &dwBytesNeeded);
dwBufferSize = dwBytesNeeded; //Size needed.
st_lpqscServiceInfo = (LPQUERY_SERVICE_CONFIG) LocalAlloc(LMEM_FIXED, dwBufferSize);
bRC = QueryServiceConfig(schHandle, st_lpqscServiceInfo, dwBufferSize, &dwBytesNeeded);
csWriteBufferTemp.Format(STR_SERVICE_STATUS_INPUT__XML_CONTENT__,st_lpqscServiceInfo->lpDisplayName,0);

Answer 1

You are almost certainly using the wrong string format parameter in _T("<SERVICE NAME = \"%S\" STARTUP_TYPE = \"0x%d\" />\r\n\r\n"). The lpServiceStartName member of SERVICE_QUERY_CONFIG and CString are both TCHAR-based so they should have matching character types regardless of whether your compiling in Unicode mode or not. In that case, you should be using %s instead of %S.

Answer 2

Thanks for all your replies and suggestions, I found the answer on another site. I don't know if this is the correct way but it works!
LPQUERY_SERVICE_CONFIG
st_lpqscServiceInfo;
SC_HANDLE schHandle;
st_lpqscServiceInfo = (LPQUERY_SERVICE_CONFIG) LocalAlloc(LPTR, 4096);
schHandle = OpenSCManager(IN_pszMachineName,SERVICES_ACTIVE_DATABASE, SERVICE_QUERY_CONFIG);
bRC = QueryServiceConfig(schHandle, st_lpqscServiceInfo, dwBufferSize, &dwBytesNeeded);
csWriteBufferTemp.Format(STR_SERVICE_STATUS_INPUT__XML_CONTENT__,st_lpqscServiceInfo->lpDisplayName,0);