Proposed resolution:

1. In [iostream.format], header <iomanip> synopsis change as indicated:

   T5 setprecision(intstreamsize n);
   T6 setw(intstreamsize n);
   

2. In [std.manip], just before p. 6 change as indicated:

   unspecified setprecision(intstreamsize n);
   

3. In [std.manip], just before p. 7 change as indicated:

   unspecified setw(intstreamsize n);
   

[ 2009 Santa Cruz: ]

No concensus for this change. There was some interest in doing the opposite fix: Change the streamsize in <ios> to int. But ultimately there was no concensus for that change either.

[ 2009-07-29 Daniel clarified wording. ]

The header <iomanip> synopsis in [iostream.format] specifies

T5 setprecision(int n);
T6 setw(int n);

The argument types should be streamsize, as in class ios_base (see [ios.base]):

streamsize precision() const;
streamsize precision(streamsize prec);
streamsize width() const;
streamsize width(streamsize wide);

(Editorial: 'wide' should probably be renamed as 'width', or maybe just 'w'.)