1. A set of function symbols with arities. 2. (Or sig) A few lines of information about the sender of an electronic mail message or newsposting. Most Unix mail and news software will automagically append a signature from a file called .signature in the user' s {home directory} to outgoing mail and news. A signature should give your real name and your {e-mail address} since, though these appear in the {headers} of your messages, they may be munged by intervening software. It is currently (1994) hip to include the URL of your home page on the World-Wide Web in your sig. The composition of one' s sig can be quite an art form, including an ASCII logo or one' s choice of witty sayings (see sig quote, fool file). However, large sigs are a waste of bandwidth, and it has been observed that the size of one' s sig block is usually inversely proportional to one' s prestige on the net. See also doubled sig, sig virus. 2. A concept very similar to {abstract base classes} except that they have their own {hierarchy} and can be applied to compiled classes. Signatures provide a means of separating subtyping and inheritance. They are implemented in C++ as patches to GCC 2.5.2 by Gerald Baumgartner . . (2001-01-05)
