diff --git a/autoload/airline.vim b/autoload/airline.vim
index cd02cf5c..794f4eea 100644
--- a/autoload/airline.vim
+++ b/autoload/airline.vim
@@ -4,22 +4,32 @@
 scriptencoding utf-8
 
 let g:airline_statusline_funcrefs = get(g:, 'airline_statusline_funcrefs', [])
+let g:airline_inactive_funcrefs = get(g:, 'airline_inactive_statusline_funcrefs', [])
 
 let s:sections = ['a','b','c','gutter','x','y','z', 'error', 'warning']
-let s:inactive_funcrefs = []
 let s:contexts = {}
 let s:core_funcrefs = [
       \ function('airline#extensions#apply'),
       \ function('airline#extensions#default#apply') ]
 
 
-function! airline#add_statusline_func(name)
-  call airline#add_statusline_funcref(function(a:name))
+function! airline#add_statusline_func(name, ...)
+  let warn = get(a:, 1, 1)
+  call airline#add_statusline_funcref(function(a:name), warn)
 endfunction
 
-function! airline#add_statusline_funcref(function)
+function! airline#add_inactive_statusline_func(name, ...)
+  let warn = get(a:, 1, 1)
+  call airline#add_inactive_statusline_funcref(function(a:name), warn)
+endfunction
+
+
+function! airline#add_statusline_funcref(function, ...)
   if index(g:airline_statusline_funcrefs, a:function) >= 0
-    call airline#util#warning(printf('The airline statusline funcref "%s" has already been added.', string(a:function)))
+    let warn = get(a:, 1, 1)
+    if warn > 0
+      call airline#util#warning(printf('The airline statusline funcref "%s" has already been added.', string(a:function)))
+    endif
     return
   endif
   call add(g:airline_statusline_funcrefs, a:function)
@@ -32,8 +42,15 @@ function! airline#remove_statusline_func(name)
   endif
 endfunction
 
-function! airline#add_inactive_statusline_func(name)
-  call add(s:inactive_funcrefs, function(a:name))
+function! airline#add_inactive_statusline_funcref(function, ...)
+  if index(g:airline_inactive_funcrefs, a:function) >= 0
+    let warn = get(a:, 1, 1)
+    if warn > 0
+      call airline#util#warning(printf('The airline inactive statusline funcref "%s" has already been added.', string(a:function)))
+    endif
+    return
+  endif
+  call add(g:airline_inactive_funcrefs, function(a:function))
 endfunction
 
 function! airline#load_theme()
@@ -168,7 +185,7 @@ function! airline#update_statusline_inactive(range)
             \ 'left_sep': g:airline_left_alt_sep,
             \ 'right_sep': g:airline_right_alt_sep }, 'keep')
     endif
-    call s:invoke_funcrefs(context, s:inactive_funcrefs)
+    call s:invoke_funcrefs(context, g:airline_inactive_funcrefs)
   endfor
 endfunction