[ Sydney: Genuine defect. 27.8.1.13 needs a cast to cast away constness. The other two places are stylistic: we could change the C-style casts to const_cast. Post-Sydney: Howard provided wording. ]

Change 27.8.1.7/1 from:

Returns: (basic_filebuf<charT,traits>*)&sb.

to:

Returns: const_cast<basic_filebuf<charT,traits>*>(&sb).

Change 27.8.1.10/1 from:

Returns: (basic_filebuf<charT,traits>*)&sb.

to:

Returns: const_cast<basic_filebuf<charT,traits>*>(&sb).

Change 27.8.1.13/1 from:

Returns: &sb.

to:

Returns: const_cast<basic_filebuf<charT,traits>*>(&sb).