WNetUseConnection SystemErrorCode 1113 No Mapping Exist - c++

Question

I am trying to convert a string into a wchar_t string to use it in a WNetUseConnection function.
Basicly its an unc name looking like this "\\remoteserver".
I get a return code 1113, which is described as:
No mapping for the Unicode character
exists in the target multi-byte code
page.
My code looks like this:
std::string serverName = "\\uncDrive";
wchar_t *remoteName = new wchar_t[ serverName.size() ];
MultiByteToWideChar(CP_ACP, 0, serverName.c_str(), serverName.size(), remoteName, serverName.size()); //also doesn't work if CP_UTF8
NETRESOURCE nr;
memset( &nr, 0, sizeof( nr ));
nr.dwType = RESOURCETYPE_DISK;
nr.lpRemoteName = remoteName;
wchar_t pswd[] = L"user"; //would have the same problem if converted and not set
wchar_t usrnm[] = L"pwd"; //would have the same problem if converted and not set
int ret = WNetUseConnection(NULL, &nr, pswd, usrnm, 0, NULL, NULL, NULL);
std::cerr << ret << std::endl;
The intersting thing is, that if remoteName is hard codede like this:
char_t remoteName[] = L"\\\\uncName";
Everything works fine. But since later on the server, user and pwd will be parameters which i get as strings, i need a way to convert them (also tried mbstowcs function with the same result).

Answer 1

MultiByteToWideChar will not 0-terminate the converted string with your current code, and therefore you get garbage characters following the converted "\uncDrive"
Use this:
std::string serverName = "\\uncDrive";
int CharsNeeded = MultiByteToWideChar(CP_ACP, 0, serverName.c_str(), serverName.size() + 1, 0, 0);
wchar_t *remoteName = new wchar_t[ CharsNeeded ];
MultiByteToWideChar(CP_ACP, 0, serverName.c_str(), serverName.size() + 1, remoteName, CharsNeeded);
This first checks with MultiByteToWideChar how many chars are needed to store the specified string and the 0-termination, then allocates the string and converts it. Note that I didn't compile/test this code, beware of typos.