explicit basic_ios(basic_streambuf<charT,traits>* sb);
Effects: Constructs an object of class basic_ios, assigning initial values to its member objects by calling init(sb).
Effects: Constructs an object of class basic_ios ([ios.base.cons]) leaving its member objects uninitialized. The object shall be initialized by calling basic_ios::init before its first use or before it is destroyed, whichever comes first; otherwise the behavior is undefined.
Remarks: The destructor does not destroy rdbuf().
void init(basic_streambuf<charT,traits>* sb);
Postconditions: The postconditions of this function are indicated in Table [tab:iostreams.basicios.init.effects].
| Element | Value | 
| rdbuf() | sb | 
| tie() | 0 | 
| rdstate() | goodbit if sb is not a null pointer, otherwise badbit. | 
| exceptions() | goodbit | 
| flags() | skipws | dec | 
| width() | 0 | 
| precision() | 6 | 
| fill() | widen(' '); | 
| getloc() | a copy of the value returned by locale() | 
| iarray | a null pointer | 
| parray | a null pointer |