https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110749
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
If you use std::fixed as the floatfield format then std::setprecision specifies
the number of digits after the decimal point:
os << (0.0 > value ? '-' : '0') << std::setw(cv.size - 1) << std::setfill('0')
<< std::setprecision(cv.pos) << std::fixed << std::abs(value);
You don't need to handle the -'- sign yourself:
os << std::setw(cv.size) << std::internal << std::setfill('0') << std::fixed <<
std::setprecision(cv.pos) << value;
This matches the output of printf("%0*.*f", cv.size, cv.pos, value)
