std::chrono...t_local_time(3)

okay bestie, this is std::chrono...t_local_time(3) from the C++ Standard Libary manual — the whole vibe is std::chrono::nonexistent_local_time, and we’re about to understand it fr fr 🕰️✨

💖 NAME 💖

std::chrono::nonexistent_local_time — std::chrono::nonexistent_local_time

🌸 Synopsis 🌸

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 choose::latest). iykyk 💅

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 take a std::chrono::local_time). slay, chrono internals, slay ✨

Inheritance diagram — file: std-chrono-nonexistent local time-inheritance.svg 🧬

🎀 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::nonexistent_local_time::nonexistent_local_time ✨

template< class Duration >
nonexistent_local_time( const std::chrono::local_time<Duration>& tp,
                        const std::chrono::local_info& i );

(1) (since C++20)

nonexistent_local_time( const nonexistent_local_time& other ) noexcept;

(2) (since C++20)

Constructs the exception object. main character constructor behavior, honestly 🫶

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. do not play with undefined behavior, bestie, that’s not the vibe 💀

2. Copy constructor. If *this and other both have dynamic type std::chrono::nonexistent_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 nonexistent_local_time to copy

😭 Exceptions 😭

May throw std::bad_alloc allocation said “not today” 😭

💅 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. lowkey iconic implementation lore ✨

👑 std::chrono::nonexistent_locale_time::operator= 👑

(the page spells it nonexistent_locale_time here, and we’re keeping that spelling exactly as-is — no cap 👀)

nonexistent_locale_time& operator=( const nonexistent_locale_time& other ) noexcept;

(since C++20)

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.

🫶 Parameters 🫶

• other — another exception object to assign with

💫 Return value 💫

*this

🌈 std::chrono::nonexistent_locale_time::what 🌈

virtual const char* what() const noexcept;

(since C++20)

Returns the explanatory string. the people’s explanatory string, honestly 💅

🫶 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(). allowed but not required: the most chill sentence in the whole standard 🦋

🌟 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)

🦋 See also 🦋

• ambiguous_local_time — exception thrown to report that a local time is ambiguous (C++20) (class)

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that’s the whole page, bestie — source: http://cppreference.com, version/date: 2024.06.10. go be the main character of your own timezone conversion, mwah 💋👑