# std::resetiosflags

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< cpp‎ | io‎ | manip

Defined in header `<iomanip>` |  |
/*unspecified*/ resetiosflags( std::ios_base::fmtflags mask ); |  |

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

### Parameters

mask | - | bitmask of the flags to clear

### Return value

An object of unspecified type such that

- if out is an object of type std::basic_ostream<CharT, Traits>, the expression out << resetiosflags(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 >> resetiosflags(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)
    {
        // reset specified flags
        str.setf(ios_base::fmtflags(0), mask);
    }

### Example

Run this code

    #include <sstream>
    #include <iostream>
    #include <iomanip>

    int main()
    {
        std::istringstream in("10 010 10 010 10 010");
        int n1, n2;

        in >> std::oct >> n1 >> n2;
        std::cout << "Parsing \"10 010\" with std::oct gives: " << n1 << ' ' << n2 << '\n';

        in >> std::dec >> n1 >> n2;
        std::cout << "Parsing \"10 010\" with std::dec gives: " << n1 << ' ' << n2 << '\n';

        in >> std::resetiosflags(std::ios_base::basefield) >> n1 >> n2;
        std::cout << "Parsing \"10 010\" with autodetect gives: " << n1 << ' ' << n2 << '\n';
    }

Output:

    Parsing "10 010" with std::oct gives: 8 8
    Parsing "10 010" with std::dec gives: 10 10
    Parsing "10 010" with autodetect gives: 10 8

### Defect reports

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

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
LWG 183 | C++98 | `resetiosflags` could only be used with streams of type std::ostream or std::istream | usable with any character stream

### See also

setf | sets specific format flag (public member function of `std::ios_base`)
setiosflags | sets the specified ios_base flags (function)

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