converting narrow string to wide string

How can i convert a narrow string to a wide string ?

I have tried this method :

string myName;
getline( cin , myName );
wstring printerName( L(myName) );  // error C3861: 'L': identifier not found
wchar_t* WprinterName = printerName.c_str(); // error C2440: 'initializing' : cannot convert from 'const wchar_t *' to 'wchar_t *'

But i get errors as listed above.

Why do i get these errors ? How can i fix them ?

Is there any other method of directly converting a narrow string to a wide string ?