_XOPEN_SOURCE
#ifdef _XOPEN_SOURCE
#if defined _XOPEN_SOURCE || defined __USE_XOPEN2K
defined _XOPEN_SOURCE || defined _XOPEN_SOURCE_EXTENDED || \
!defined _XOPEN_SOURCE && !defined _XOPEN_SOURCE_EXTENDED && \
# if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
#if defined _POSIX_SOURCE || _POSIX_C_SOURCE >= 1 || defined _XOPEN_SOURCE
#if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
#ifdef _XOPEN_SOURCE
# if (_XOPEN_SOURCE - 0) >= 500
# if (_XOPEN_SOURCE - 0) >= 600
#ifndef _XOPEN_SOURCE
#ifndef _XOPEN_SOURCE