std::chrono::file_clock

 

C++

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General utilities Date and time Function objects Formatting library (C++20) bitset hash (C++11) Relational operators (deprecated in C++20) rel_ops::operator!=rel_ops::operator> rel_ops::operator<=rel_ops::operator>= Integer comparison functions cmp_equalcmp_lesscmp_less_than (C++20)(C++20)(C++20)    cmp_not_equalcmp_greatercmp_greater_than (C++20)(C++20)(C++20) in_range (C++20) Swap and type operations swap ranges::swap (C++20) exchange (C++14) declval (C++11) to_underlying (C++23) forward (C++11) forward_like (C++23) move (C++11) move_if_noexcept (C++11) as_const (C++17) Common vocabulary types pair tuple (C++11) optional (C++17) any (C++17) variant (C++17) tuple_size (C++11) tuple_element (C++11) apply (C++17) make_from_tuple (C++17) expected (C++23) Elementary string conversions to_chars (C++17) from_chars (C++17) chars_format (C++17)

 

Date and time utilities

Time point
time_point (C++11)	clock_time_conversion (C++20)	clock_cast (C++20)
Duration
duration (C++11)
Clocks
system_clock (C++11) steady_clock (C++11) high_resolution_clock (C++11)	is_clock (C++20) utc_clock (C++20) tai_clock (C++20)	gps_clock (C++20) file_clock (C++20) local_t (C++20)
Time of day
is_amis_pm (C++20)(C++20)	make12make24 (C++20)(C++20)	hh_mm_ss (C++20)
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Time zones
tzdb (C++20) tzdb_list (C++20) get_tzdbget_tzdb_listreload_tzdbremote_version (C++20)(C++20)(C++20)(C++20) sys_info (C++20)	local_info (C++20) nonexistent_local_time (C++20) ambiguous_local_time (C++20) locate_zone (C++20) current_zone (C++20) time_zone (C++20) choose (C++20)	zoned_traits (C++20) zoned_time (C++20) time_zone_link (C++20) leap_second (C++20) leap_second_info (C++20) get_leap_second_info (C++20)
chrono I/O
parse (C++20)
C-style date and time

 

std::chrono::file_clock

Member functions

file_clock::now

file_clock::to_sysfile_clock::from_sys (provided only if to_utc and from_utc are not provided)

file_clock::to_utcfile_clock::from_utc (provided only if to_sys and from_sys are not provided)

Time point I/O

operator<<

formatter<std::chrono::file_time>

from_stream

 

Defined in header <chrono>
using file_clock = /* see below */;		(since C++20)

std::chrono::file_clock is an alias for the clock used for std::filesystem::file_time_type. Its epoch is unspecified.

file_clock meets the TrivialClock requirements.

Time point family

Defined in namespace std::chrono
template<class Duration> using file_time = std::chrono::time_point<std::chrono::file_clock, Duration>;		(since C++20)

operator<<(std::chrono::file_time) (C++20)	performs stream output on a file_time (function template)
from_stream(std::chrono::file_time) (C++20)	parses a file_time from a stream according to the provided format (function template)
std::formatter<std::chrono::file_time> (C++20)	formatting support for file_time (class template specialization)

Member types

Member type	Definition
rep	signed arithmetic type representing the number of ticks in the clock's duration
period	a std::ratio type representing the tick period of the clock, in seconds
duration	std::chrono::duration<rep, period>, capable of representing negative durations
time_point	std::chrono::time_point<std::chrono::file_clock>

Member constants

constexpr bool is_steady [static]

true if the time between ticks is always constant, i.e. calls to now() return values that increase monotonically even in case of some external clock adjustment, otherwise false (public static member constant)

Member functions

file_clock provides exactly one of the following two pairs of static member functions:

• to_utc and from_utc; or
• to_sys and from_sys.

now [static]	returns a std::chrono::time_point representing the current point in time (public static member function)
to_utcfrom_utc [static] (optional)	converts between file_time and utc_time (public static member function)
to_sysfrom_sys [static] (optional)	converts between file_time and sys_time (public static member function)