使用Vimdiff出现“Cannot read temp file"的问题

当从Vim7.3升级到Vim7.4之后，我发现vimdiff的功能不能用了，老是出现”Cannot read temp file“的问题。当我确认了temp文件夹的访问权限之后，我个人感觉还是MyDiff()函数出了问题。

修改MyDiff()如下，问题解决。

function! MyDiff()
   let opt = '-a --binary '
   if &diffopt =~ 'icase' | let opt = opt . '-i ' | endif
   if &diffopt =~ 'iwhite' | let opt = opt . '-b ' | endif
   let arg1 = v:fname_in
   if arg1 =~ ' ' | let arg1 = '"' . arg1 . '"' | endif
   let arg2 = v:fname_new
   if arg2 =~ ' ' | let arg2 = '"' . arg2 . '"' | endif
   let arg3 = v:fname_out
   if arg3 =~ ' ' | let arg3 = '"' . arg3 . '"' | endif
   if $VIMRUNTIME =~ ' '
     if &sh =~ '\<cmd'
       if empty(&shellxquote)
         let l:shxq_sav = ''
         set shellxquote&
       endif
       let cmd = '"' . $VIMRUNTIME . '\diff"'
     else
       let cmd = substitute($VIMRUNTIME, ' ', '" ', '') . '\diff"'
     endif
   else
     let cmd = $VIMRUNTIME . '\diff'
   endif
   "echo '!' . cmd . ' ' . opt . arg1 . ' ' . arg2 . ' > ' . arg3
   silent execute '!' . cmd . ' ' . opt . arg1 . ' ' . arg2 . ' > ' . arg3
   if exists('l:shxq_sav')
     let &shellxquote=l:shxq_sav
   endif
 endfunction