Annex D (normative) Compatibility features [depr]

D.13 char* streams [depr.str.strstreams]

D.13.3 Class istrstream [depr.istrstream]

D.13.3.3 Member functions [depr.istrstream.members]

strstreambuf* rdbuf() const;
Returns: const_cast<strstreambuf*>(&sb).
char* str();
Returns: rdbuf()->str().