Convert SID to String

Question

I'm not a C++ developer, so I guess it's just my fault that my program doesn't work. I want to look up the SID for a windows group and return a readable SID.

wchar_t* SpcLookupName(LPCTSTR lpszSystemName, LPCTSTR lpszAccountName) {

PSID         Sid;
DWORD        cbReferencedDomainName, cbSid;
LPTSTR       ReferencedDomainName;
SID_NAME_USE eUse;

cbReferencedDomainName = cbSid = 0;
if (LookupAccountName(lpszSystemName, lpszAccountName, 0, &cbSid,
                    0, &cbReferencedDomainName, &eUse)) {
    SetLastError(ERROR_NONE_MAPPED);
    return 0;
}

if (GetLastError(  ) != ERROR_INSUFFICIENT_BUFFER) return 0;

if (!(Sid = (PSID)LocalAlloc(LMEM_FIXED, cbSid))) return 0;

ReferencedDomainName = (LPTSTR)LocalAlloc(LMEM_FIXED, cbReferencedDomainName);

if (!ReferencedDomainName) {
    LocalFree(Sid);
    return 0;
}

if (!LookupAccountName(lpszSystemName, lpszAccountName, Sid, &cbSid,
                     ReferencedDomainName, &cbReferencedDomainName, &eUse)) {
    LocalFree(ReferencedDomainName);
    LocalFree(Sid);
    return 0;
}

wchar_t* psz;

// Loading ConvertSidToStringSid
typedef BOOL (WINAPI *tConvertSidToStringSid)(PSID,wchar_t*);

tConvertSidToStringSid pConvertSidToStringSid=0;

HINSTANCE handle = ::LoadLibrary("Advapi32.dll");

pConvertSidToStringSid = (tConvertSidToStringSid) ::GetProcAddress(handle, "ConvertSidToStringSidA");

if(pConvertSidToStringSid(Sid, psz)){                               
    return psz;
}
}

My problem is that the function returns only some strange characters and not the SID, why?