Returns an objectmanip of unspecified type such that, given astd::basic_istream<CharT, Traits> objectis, the expressionis>> manip callsfrom_stream (unqualified, to enableargument-dependent lookup) as follows:

The expressionis>> manip is an lvalue of typestd::basic_istream<CharT, Traits> with the valueis.

These overloads participate in overload resolution only if the correspondingfrom_stream expression is well-formed.

Implementations are recommended to make it difficult to use potentially dangling references to the format string, e.g., by making return types non-movable and preventingoperator>> from accepting lvalues of return types.

[edit]Parameters

[edit]Format string

The format string consists of zero or more conversion specifiers and ordinary characters. Each ordinary character, excluding whitespace characters and the terminating null character, matches one identical character from the input stream, or causes the function to fail if the next character on the stream does not compare equal.

Each whitespace character matches zero or more whitespace characters in the input stream.

Each unmodified conversion specifier begins with a% character followed by a character that determines the behavior of the specifier. Some conversion specifiers have a modified form in which anE orO modifier character is inserted after the% character. Some conversion specifiers have a modified form in which a width parameter given as a positive decimal integer (shown asN below) is inserted after the% character. Each conversion specifier causes the matched characters to be interpreted as parts of date and time types according to the table below.

A character sequence in the format string that begins with a% but does not match one of the conversion specifiers below is interpreted as ordinary characters.

Iffrom_stream fails to parse everything specified by the format string, or if insufficient information is parsed to specify a complete result, or if parsing discloses contradictory information,is.setstate(std::ios_base::failbit) is called.

The following conversion specifiers are available:

[edit]Example

#include <chrono>#include <iostream>#include <locale>#include <sstream> int main(){auto parse=[&](auto str,auto fmt,auto o){std::istringstream is{str};        is.imbue(std::locale("en_US.utf-8"));        is>> std::chrono::parse(fmt, o);        is.fail()?std::cout<<"Parse failed!\n":std::cout<< o<<'\n';};    parse("01:02:03","%H:%M:%S",std::chrono::hours{});    parse("01:02:03","%H:%M:%S",std::chrono::minutes{});    parse("01:02:03","%H:%M:%S",std::chrono::seconds{});}

1h62min3723s

[edit]Defect reports

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

[edit]See also

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