When used in an expression out << setiosflags(mask) or in >> setiosflags(mask), sets all format flags of the stream out or in as specified by the mask.

Parameters

Return value

An object of unspecified type such that

• if out is an object of type std::basic_ostream<CharT, Traits>, the expression out << setiosflags(mask)
  • has type std::basic_ostream<CharT, Traits>&
  • has value out
  • behaves as if it called f(out, mask)
• if in is an object of type std::basic_istream<CharT, Traits>, the expression in >> setiosflags(mask)
  • has type std::basic_istream<CharT, Traits>&
  • has value in
  • behaves as if it called f(in, mask)

where the function f is defined as:

void f(std::ios_base& str, std::ios_base::fmtflags mask)
{
    // set specified flags
    str.setf(mask);
}

Example

#include <iomanip>
#include <iostream>

int main()
{
    std::cout << std::resetiosflags(std::ios_base::dec) 
              << std::setiosflags(  std::ios_base::hex
                                  | std::ios_base::uppercase
                                  | std::ios_base::showbase) << 42 << '\n';
}

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also