C++ named requirements: FormattedInputFunction

Requirements

A FormattedInputFunction is a stream input function that performs the following:

• Constructs an object of type basic_istream::sentry with automatic storage duration and with the noskipws argument set to false , which performs the following:

• if eofbit or badbit are set on the input stream, sets the failbit as well, and if exceptions on failbit are enabled in this input stream's exception mask ( ( exceptions ( ) & failbit ) ! = 0 ), throws ios_base::failure .
• flushes the tie()'d output stream, if applicable.
• if ios_base::skipws flag is set on this input stream, extracts and discards characters from the input stream until one of the following becomes true:

• the next available character on the input stream is not a whitespace character, as tested by the std::ctype facet of the locale currently imbued in this input stream. The non-whitespace character is not extracted.
• the end of the stream is reached, in which case failbit and eofbit are set and if the stream is on for exceptions on one of these bits, ios_base::failure is thrown.

• Checks the status of the sentry by calling sentry::operator bool() , which is equivalent to basic_ios::good .
• If the sentry returned false or sentry's constructor threw an exception, no input takes place.
• If the sentry returned true , performs the input as if by calling rdbuf ( ) - > sbumpc ( ) or rdbuf ( ) - > sgetc ( ) .

• if the end of the stream is reached (the call to rdbuf ( ) - > sbumpc ( ) or rdbuf ( ) - > sgetc ( ) returns Traits :: eof ( ) ), sets eofbit . If exceptions on eofbit are enabled in this stream's exception mask ( ( exceptions ( ) & eofbit ) ! = 0 ), throws ios_base::failure .
• if an exception is thrown during input, sets badbit in the input stream. If exceptions on badbit are enabled in this stream's exception mask ( ( exceptions ( ) & badbit ) ! = 0 ), the exception is also rethrown.
• If no exception was thrown, returns * this .

• In any event, whether terminating by exception or returning, the sentry's destructor is called before leaving this function.

Standard library

The following standard library functions are FormattedInputFunction s .

• basic_istream::operator>> (int, long, double, void*, bool)
• operator>> (std::basic_istream, char&)
• operator>> (std::basic_istream, char*)
• operator>> (std::basic_istream, std::bitset)
• operator>> (std::basic_istream, std::string)
• operator>> , when called on the return value of std::get_money

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 160	C++98	the process of determining whether the exception caught is rethrown mentioned a non-existing function exception()	corrected to exceptions()