std::chrono::system_clock::to_time_t (3) Linux Manual Page
std::chrono::system_clock::to_time_t – std::chrono::system_clock::to_time_t
Synopsis
static std::time_t to_time_t(const time_point &t) noexcept;
(since C++ 11)Converts t to a std::time_t type.
If std::time_t has lower precision, it is implementation-defined whether the value is rounded or truncated.
Parameters
t – system clock time point to convert
Return value
A std::time_t value representing t.
See also
from_time_t converts std::time_t to a system clock time point
[static]