Robert:
I cannot reproduce this with a recent CVS g++/libstdc++-v3:
#include <iostream>
#include <iomanip>
int main()
{
using namespace std;
cout << setw(20) << 2.3 << endl;
}
%COMP.sh list01.cc
<bkoz@purist> /mnt/hd/soma/src.gcc/libstdc++-v3.cvs/testsuite
%a.out
2.3
...pretty much what i'd expect.
-benjamin