std::noskipws

ios_base& noskipws (ios_base& str);

Do not skip whitespaces

Clears the skipws format flag for the str stream.

When the skipws format flag is not set, all operations on the stream consider initial whitespace characters as valid content to be extracted.

Tab spaces, carriage returns and blank spaces are all considered whitespaces (see isspace).

This flag can be set with the skipws manipulator. When set, as many initial whitespace characters as necessary are read and discarded from the stream until a non-whitespace character is found. This would apply to every formatted input operation performed with operator>> on the stream.

Notice that many extraction operations consider the whitespaces themselves as the terminating character, therefore, with the skipws flag disabled, some extraction operations may extract no characters at all from the stream.

For standard streams, the skipws flag is set on initialization.

Parameters

str: Stream object whose format flag is affected.
Because this function is a manipulator, it is designed to be used alone with no arguments in conjunction with the insertion (<<) and extraction (>>) operations on streams (see example below).

Return Value

Argument str.

Example

// skipws flag example
#include <iostream>     // std::cout, std::skipws, std::noskipws
#include <sstream>      // std::istringstream

int main () {
  char a, b, c;

  std::istringstream iss ("  123");
  iss >> std::skipws >> a >> b >> c;
  std::cout << a << b << c << '\n';

  iss.seekg(0);
  iss >> std::noskipws >> a >> b >> c;
  std::cout << a << b << c << '\n';
  return 0;
}

Output:

123
  1

Notice that in the first set of extractions, the leading spaces were ignored, while in the second they were extracted as valid characters.

Data races

Modifies str. Concurrent access to the same stream object may cause data races.

Exception safety

Basic guarantee: if an exception is thrown, str is in a valid state.

types

manipulators

other functions