This page is a snapshot from the LWG issues list, see the Library Active Issues List for more information and the meaning of NAD status.

### 1148. Wrong argument type of I/O stream manipulators `setprecision()` and `setw()`

Section: 31.7 [iostream.format] Status: NAD Submitter: Marc Steinbach Opened: 2009-06-20 Last modified: 2016-01-28

Priority: Not Prioritized

View all other issues in [iostream.format].

View all issues with NAD status.

Discussion:

The header `<iomanip>` synopsis in 31.7 [iostream.format] specifies

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

The argument types should be streamsize, as in class `ios_base` (see 31.5.2 [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'.)

[ 2009-07-29 Daniel clarified wording. ]

[ 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.

Proposed resolution:

1. In 31.7 [iostream.format], header `<iomanip>` synopsis change as indicated:

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

2. In 31.7.7 [std.manip], just before p. 6 change as indicated:

   >     unspecified setprecision(intstreamsize n);

3. In 31.7.7 [std.manip], just before p. 7 change as indicated:

   >     unspecified setw(intstreamsize n);