localtime (GNU Gnulib)

Gnulib module: localtime

Portability problems fixed by Gnulib:

On native Windows platforms (mingw, MSVC), this function works incorrectly when the environment variable TZ has been set by Cygwin.

Portability problems not fixed by Gnulib:

On some platforms, this function loops forever for values near extrema (such as the year -2**31): Mac OS X 10.6. You can use the time_rz module to work around the problem.
On some platforms, this function returns nonsense values for unsupported arguments (like 2^56), rather than failing: FreeBSD 10.
On some platforms, this function yields incorrect values for timestamps before the year 1: MacOS X 10.5, Solaris 11.3.
On some platforms, this function returns NULL for negative arguments, that is, for timestamps before 1970-01-01 00:00:00 local time: mingw, MSVC.
Native Windows platforms (mingw, MSVC) support only a subset of time zones supported by GNU or specified by POSIX. See tzset.