__USE_XOPEN2K
#if defined _XOPEN_SOURCE || defined __USE_XOPEN2K
&& (defined __STRICT_ANSI__ || defined __USE_XOPEN2K)
&& (defined __STRICT_ANSI__ || defined __USE_XOPEN2K)
|| (defined __USE_XOPEN && !defined __USE_XOPEN2K)
#if defined __USE_LARGEFILE || defined __USE_XOPEN2K
#if defined __USE_XOPEN && !defined __USE_XOPEN2K && !defined __USE_GNU