std::resetiosflags

 

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