Path: utzoo!attcan!uunet!brunix!sdm
From: sdm@cs.brown.edu (Scott Meyers)
Newsgroups: comp.lang.c++
Subject: cfront error message could use improvement
Message-ID: <33825@brunix.UUCP>
Date: 23 Mar 90 15:12:51 GMT
Sender: news@brunix.UUCP
Reply-To: sdm@cs.brown.edu (Scott Meyers)
Organization: Brown University Department of Computer Science
Lines: 34

Okay, so mystifying error messages are nothing to get excited about, but
this one is so good I thought it might be of wider interest.  Try
passing a stream by value:

     #include <iostream.h>

     void foo( ostream s ) // Oops -- meant ostream&
     {
       s << "Foo!";
     }

     main()
     {
       foo( cout );
     }

Here's the error message:

  "streamvalue.C", line 11: error:
     ostream::ostream() cannot access ios::ios(): private  member

Things to note:
  1.  The line number given is the last line of the file.
  2.  One is left wondering how it is that one is trying to call a
      private constructor.
  3.  One begins to wonder why a constructor is private in the first
      place... 

Perhaps the error message gurus at AT&T could look into improving this
kind of behavior in 2.1?


Scott
sdm@cs.brown.edu