NAME¶

std::chrono::ambiguous_local_time - std::chrono::ambiguous_local_time

Synopsis¶

Defined in header <chrono>
class ambiguous_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 ambiguous std::chrono::local_time to a std::chrono::sys_time
without specifying a std::chrono::choose (such as choose::earliest or
choose::latest).

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::local_time).

std-chrono-ambiguous 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)

std::chrono::ambiguous_local_time::ambiguous_local_time

template< class Duration >

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

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

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 ambiguous. It could be\n"
<< tp << ' ' << i.first.abbrev << " == "
<< tp - i.first.offset << " UTC or\n"
<< tp << ' ' << i.second.abbrev << " == "
<< tp - i.second.offset << " UTC";

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

Parameters¶

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

Exceptions¶

May throw std::bad_alloc

Notes¶

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.

std::chrono::ambiguous_locale_time::operator=

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

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

Parameters¶

other - another exception object to assign with

Return value¶

*this

std::chrono::ambiguous_locale_time::what

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

Returns the explanatory string.

Parameters¶

(none)

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.

Notes¶

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)