+" Function: SigFileReadable()
+" Purpose: Check if the signature file is readable
+"---------------------------------------------------------------------------
+func! SigFileReadable(sigfile)
+ let filename = expand(a:sigfile)
+ if !filereadable(filename)
+ echoerr "E484: Can't open file " . filename
+ return v:false
+ endif
+
+ return v:true
+endfunc
+