diff --git a/plugin/defaults.vim b/plugin/defaults.vim
index 01ba6d1..afa4b9a 100644
--- a/plugin/defaults.vim
+++ b/plugin/defaults.vim
@@ -35,8 +35,8 @@ endif
 
 " Generic C, C++, Objective-C
 if !exists('g:formatdef_clangformat')
-    let s:configfile_def = "'clang-format -lines='.a:firstline.':'.a:lastline.' --assume-filename='.bufname('%').' -style=file'"
-    let s:noconfigfile_def = "'clang-format -lines='.a:firstline.':'.a:lastline.' --assume-filename='.bufname('%').' -style=\"{BasedOnStyle: WebKit, AlignTrailingComments: true, '.(&textwidth ? 'ColumnLimit: '.&textwidth.', ' : '').(&expandtab ? 'UseTab: Never, IndentWidth: '.shiftwidth() : 'UseTab: Always').'}\"'"
+    let s:configfile_def = "'clang-format -lines='.a:firstline.':'.a:lastline.' --assume-filename=\"'.expand('%:p').'\" -style=file'"
+    let s:noconfigfile_def = "'clang-format -lines='.a:firstline.':'.a:lastline.' --assume-filename=\"'.expand('%:p').'\" -style=\"{BasedOnStyle: WebKit, AlignTrailingComments: true, '.(&textwidth ? 'ColumnLimit: '.&textwidth.', ' : '').(&expandtab ? 'UseTab: Never, IndentWidth: '.shiftwidth() : 'UseTab: Always').'}\"'"
     let g:formatdef_clangformat = "g:ClangFormatConfigFileExists() ? (" . s:configfile_def . ") : (" . s:noconfigfile_def . ")"
 endif