alias
1. <operating system> A name, usually short and easy to remember and
type, that is translated into another name or string, usually long and difficult
to remember or type. Most command interpreters (e.g. Unix's csh) allow the user
to define aliases for commands, e.g. "alias l ls -al". These are loaded into
memory when the interpreter starts and are expanded without needing to refer to
any file.
2. <networking> One of several alternative hostnames with the same
Internet address. E.g. in the Unix hosts database (/etc/hosts or NIS map) the
first field on a line is the Internet address, the next is the official hostname
(the "canonical name" or "CNAME"), and any others are aliases.
Hostname aliases often indicate that the host with that alias provides a
particular network service such as archie, finger, FTP, or World-Wide Web. The
assignment of services to computers can then be changed simply by moving an
alias (e.g. www.doc.ic.ac.uk) from one Internet address to another, without the
clients needing to be aware of the change.
3. <file system> The name used by Apple computer, Inc. for symbolic links
when they added them to the System 7 operating system in 1991.
(1997-10-22)
4. <programming> Two names (identifiers), usually of local or global
variables, that refer to the same resource (memory location) are said to be
aliased. Although names introduced in programming languages are typically mapped
to different memory locations, aliasing can be introduced by the use of address
arithmetic and pointers or language-specific features, like C++ references.
Statically deciding (e.g. via a program analysis executed by a sophisticated
compiler) which locations of a program will be aliased at run time is an
undecidable problem.
[G. Ramalingam: "The Undecidability of Aliasing", ACM Transactions on
Programming Languages and Systems (TOPLAS), Volume 16, Issue 5, September 1994,
Pages: 1467 - 1471, ISSN:0164-0925.]
(2004-09-12)
Nearby terms:
Algorithmic Test Case Generation « ALGY « ALIAS «
alias
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