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std::chrono::nonexistent_local_time(3) C++ Standard Libary std::chrono::nonexistent_local_time(3)


std::chrono::nonexistent_local_time - std::chrono::nonexistent_local_time


Defined in header <chrono>
class nonexistent_local_time; (since C++20)

Defines a type of object to be thrown as exception to report that an attempt was
made to convert a nonexistent std::chrono::local_time to a std::chrono::sys_time
without specifying a std::chrono::choose (such as choose::earliest or

This exception is thrown by std::chrono::time_zone::to_sys and functions that call
it (such as the constructors of std::chrono::zoned_time that takes a

std-chrono-nonexistent local time-inheritance.svg

Inheritance diagram

Member functions

constructor constructs the exception object
(public member function)
operator= replaces the exception object
(public member function)
what returns the explanatory string
(public member function)


template< class Duration >

nonexistent_local_time( const std::chrono::local_time<Duration>& (1) (since C++20)

const std::chrono::local_info& i );
nonexistent_local_time( const nonexistent_local_time& other ) (2) (since C++20)

Constructs the exception object.

1) The explanatory string returned by what() is equivalent to that produced by
os.str() after the following code:

std::ostringstream os;
os << tp << " is in a gap between\n"
<< std::chrono::local_seconds(i.first.end.time_since_epoch()) + i.first.offset
<< ' ' << i.first.abbrev << " and\n"
<< std::chrono::local_seconds(i.second.begin.time_since_epoch()) + i.second.offset
<< ' ' << i.second.abbrev
<< " which are both equivalent to\n"
<< i.first.end << " UTC";

The behavior is undefined if i.result != std::chrono::local_info::nonexistent.
2) Copy constructor. If *this and other both have dynamic type
std::chrono::nonexistent_local_time then std::strcmp(what(), other.what()) == 0.


tp - the time point for which conversion was attempted
i - a std::chrono::local_info describing the result of the conversion attempt
other - another nonexistent_local_time to copy


May throw std::bad_alloc


Because copying a standard library class derived from std::exception is not
permitted to throw exceptions, this message is typically stored internally as a
separately-allocated reference-counted string.


nonexistent_locale_time& operator=( const nonexistent_locale_time& (since C++20)
other ) noexcept;

Assigns the contents with those of other. If *this and other both have dynamic type
std::chrono::nonexistent_locale_time then std::strcmp(what(), other.what()) == 0
after assignment.


other - another exception object to assign with

Return value



virtual const char* what() const noexcept; (since C++20)

Returns the explanatory string.



Return value

Pointer to a null-terminated string with explanatory information. The string is
suitable for conversion and display as a std::wstring. The pointer is guaranteed to
be valid at least until the exception object from which it is obtained is destroyed,
or until a non-const member function (e.g. copy assignment operator) on the
exception object is called.


Implementations are allowed but not required to override what().

Inherited from std::runtime_error

Inherited from std::exception

Member functions

destructor destroys the exception object
[virtual] (virtual public member function of std::exception)
what returns an explanatory string
[virtual] (virtual public member function of std::exception)