F_DUPFD
#define F_DUPFD_CLOEXEC_MAYBE F_DUPFD
if ((nfd = _fcntl(fd, F_DUPFD, __rpc_minfd)) == -1)
case F_DUPFD:
case F_DUPFD:
case F_DUPFD:
case F_DUPFD:
if ((fd2 = fcntl(fd1, F_DUPFD, 10)) < 0)
case F_DUPFD:
oclo_fdup_common(c, 0, F_DUPFD);