AC_DEFUN([LFTP_NEED_TRIO],[

   AC_CHECK_FUNCS(vsnprintf snprintf)

   AC_CACHE_CHECK([if trio library is needed], ac_cv_need_trio,

   [

      ac_cv_need_trio=no;

      if test x$ac_cv_func_vsnprintf != xyes -o x$ac_cv_func_snprintf != xyes; then

	 ac_cv_need_trio="yes (because there is no system snprintf/vsnprintf functions)"

      else

      AC_RUN_IFELSE([AC_LANG_SOURCE([[

	 int main()

	 {

	    unsigned long long x=0,x1;

	    long long y=0,y1;

	    char buf[128];

	    x=~x;

	    sscanf("0","%llu",&x);

	    if(x!=0) return 1;

	    y=~y;

	    sscanf("0","%lld",&y);

	    if(y!=0) return 1;

	    x=~x;

	    sprintf(buf,"%lld %llu",y,x);

	    sscanf (buf,"%lld %llu",&y1,&x1;;

	    if(x!=x1 || y!=y1)

	       return 1;

	    return 0;

	 }]])],[],[ac_cv_need_trio="yes (because %lld fails)"],[ac_cv_need_trio="no (assumed)"])

      fi

   ])

   case $ac_cv_need_trio in

   yes*)

      ac_cv_need_trio=yes

      AC_DEFINE(TRIO_REPLACE_STDIO, 1, [replace system's printf functions])

      LFTP_CHECK_LIBM

      ;;

   *)

      ac_cv_need_trio=no

      ;;

   esac

   AM_CONDITIONAL(NEED_TRIO, [test "$ac_cv_need_trio" = yes])

])