_POSIX_VERSION
# ifdef _POSIX_VERSION
# ifdef _POSIX_VERSION
# if _POSIX_VERSION >= 199500 && !defined(USESETEUID)
# if defined _POSIX_VERSION && _POSIX_VERSION <= 200809
# if _POSIX_VERSION < 200809
# if _POSIX_VERSION < 198808 && !USG_COMPAT
#if (200809 < _POSIX_VERSION \
&& defined TM_GMTOFF && (200809 < _POSIX_VERSION || ! UNINIT_TRAP))
#ifndef _POSIX_VERSION
return (_POSIX_VERSION); /* current POSIX version */