- void error (string) const;
- void programming_error (string) const;
- void non_fatal_error (string) const;
- void warning (string) const;
- void message (string) const;
- void debug_output (string) const;
+ void error (const string&) const;
+ void programming_error (const string&) const;
+ void non_fatal_error (const string&) const;
+ void warning (const string&) const;
+ void message (const string&) const;
+ void debug_output (const string&) const;