diff --git a/ldoc/doc.lua b/ldoc/doc.lua
index ecdb268..c79ca9b 100644
--- a/ldoc/doc.lua
+++ b/ldoc/doc.lua
@@ -1100,6 +1100,11 @@ function Module:process_see_reference (s,modules,istype)
    else
       lua_manual_ref = global.lua_manual_ref
    end
+   -- pure C projects use global lookup (no namespaces)
+   if ldoc.global_lookup == nil then
+      local using_c = ldoc.parse_extra and ldoc.parse_extra.C
+      ldoc.global_lookup = using_c or false
+   end
 
    -- is this a fully qualified module name?
    local mod_ref = modules.by_name[s]
diff --git a/ldoc/markup.lua b/ldoc/markup.lua
index c7a75e3..fe2446b 100644
--- a/ldoc/markup.lua
+++ b/ldoc/markup.lua
@@ -243,16 +243,19 @@ local formatters =
 
 
 local function get_formatter(format)
+   local used_format = format
    local formatter = (formatters[format] or generic_formatter)(format)
-   if formatter then return formatter end
-
-   for name, f in pairs(formatters) do
-      formatter = f(name)
-      if formatter then
-         print('format: '..format..' not found, using '..name)
-         return formatter
-      end
-   end
+   if not formatter then -- try another equivalent processor
+		for name, f in pairs(formatters) do
+			formatter = f(name)
+			if formatter then
+				print('format: '..format..' not found, using '..name)
+				used_format = name
+				break
+			end
+		end
+	end
+	return formatter, used_format
 end
 
 local function text_processor(ldoc)
@@ -299,9 +302,13 @@ end
 local function get_processor(ldoc, format)
    if format == 'plain' then return text_processor(ldoc) end
 
-   local formatter = get_formatter(format)
+   local formatter,actual_format = get_formatter(format)
    if formatter then
       markup.plain = false
+      -- AFAIK only markdown.lua has underscore-in-identifier problem...
+      if ldoc.dont_escape_underscore ~= nil then
+         ldoc.dont_escape_underscore = actual_format ~= 'markdown'
+      end      
       return markdown_processor(ldoc, formatter)
    end