POSIX

“POSIX” == “Portable Operating System Interface”

• POSIX.1-2008

use “clock_gettime” instead of “gettimeofday”

在 POSIX 2008 時，已經把 gettimeofday 淘汰，推薦使用 clock_gettime ， 目前 Linux 和 FreeBSD 都有支援，但是 Mac OS 和 Windows 都不支援。

POSIX.1-2008 marks gettimeofday() as obsolete, recommending
the use of clock_gettime(2) instead.

• Linux FAQ for clock_gettime(CLOCK_REALTIME)
• Is gettimeofday() guaranteed to be of microsecond resolution?
• POSIX timers clock_gettime 分析
• cppreference - Date and time utilities
• std::chrono : typesafe time keeping in C++
• libstdc++ - chrono.cc
• libc++ - chrono.cpp