@@ -4,8 +4,10 @@
 --  ? simple command line driver for the cortav library
 local ct = require 'cortav'
 local ss = require 'sirsem'
 
+local native = _G.native
+
 local default_mode = {
 	['render:format'] = 'html';
 	['html:gen-styles'] = true;
 	['groff:color'] = true;
@@ -226,16 +228,22 @@
 	if ss.exn.is(e) then
 		str = e.kind.desc
 	end
 	local color = false
-	if log:seek() == nil then
-		-- this is not a very reliable heuristic for detecting
-		-- attachment to a tty but it's better than nothing
-		if os.getenv('COLORTERM') then
+	if native then
+		if native.posix.isatty(log) then
 			color = true
-		else
-			local term = os.getenv('TERM')
-			if term:find 'color' then color = true end
+		end
+	else
+		if log:seek() == nil then
+			-- this is not a very reliable heuristic for detecting
+			-- attachment to a tty but it's better than nothing
+			if os.getenv('COLORTERM') then
+				color = true
+			else
+				local term = os.getenv('TERM')
+				if term:find 'color' then color = true end
+			end
 		end
 	end
 	if color then
 		str = string.format('\27[1;31m%s\27[m', str)