+ if (nargs >= 3)
+ {
+ register Lisp_Object tem;
+
+ buffer = tem = args[2];
+ if (!(EQ (tem, Qnil)
+ || EQ (tem, Qt)
+ || XFASTINT (tem) == 0))
+ {
+ buffer = Fget_buffer (tem);
+ CHECK_BUFFER (buffer, 2);
+ }
+ }
+ else
+ buffer = Qnil;
+
+ /* Make sure that the child will be able to chdir to the current
+ buffer's current directory, or its unhandled equivalent. We
+ can't just have the child check for an error when it does the
+ chdir, since it's in a vfork.
+
+ We have to GCPRO around this because Fexpand_file_name,
+ Funhandled_file_name_directory, and Ffile_accessible_directory_p
+ might call a file name handling function. The argument list is
+ protected by the caller, so all we really have to worry about is
+ buffer. */