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(1)
any <a href="index.html#assignment context"><dfn>assignment context</dfn></a> (q.v.)
in which the destination
(left-hand side) has pointer type;
<br>
<br>
(2)
an <TT>==</TT> or <TT>!=</TT> comparison in which one side has
pointer type;
<br>
<br>
(3)
the second and third operands of the <TT>?:</TT> operator, when one
of them is a pointer;
and

<br>
<br>
(4)
the operand of a pointer cast,
such as <TT>(char&nbsp;*)</TT> or <TT>(void&nbsp;*)</TT>.
<br>
<br>
See question <a href="../null/null2.html">5.2</a>.
</DD><DT><a name="pun">pun</a></DT>
<DD>vt.
To
contrive to

treat
an object
as if it had
a different type,
usually by using a union
or an expression of the form <TT>*(othertype&nbsp;*)&amp;object</TT>.
</DD><DT><a name="ragged array">ragged array</a></DT>
<DD>n.
An array,
usually simulated with pointers,
in which the rows are not necessarily of the same length.
See also <a href="index.html#dope vector"><dfn>dope vector</dfn></a>.
See questions <a href="../aryptr/dynmuldimary.html">6.16</a>
and <a href="../misc/ragged.html">20.2</a>.
</DD><DT><a name="reentrant">reentrant</a></DT>
<DD>adj.
Refers to code which can safely be called
from interrupts
or in other circumstances
in which it is possible
that another instance of the code is simultaneously active.
Reentrant code has to be very careful of the way it
manipulates data:
the data
must either all be local,
or else protected by semaphores or
the like.
</DD><DT><a name="RFC">RFC</a></DT>
<DD>n.
An internet
Request For Comments document,
available by ftp from ds.internic.net and many other sites.
</DD><DT><a name="rhs">rhs</a></DT>
<DD>n.
The right-hand side,
usually of an assignment,
or more generally,
of any binary operator.
</DD><DT><a name="rvalue">rvalue</a></DT>
<DD>n.
Originally,
an
expression
which could appear
on the right-hand sign of an assignment operator.
More generally,
any
value which can participate in an expression or be
assigned to some other variable.


In the assignment
<pre>
	a = b;
</pre>
<TT>b</TT> is an rvalue, and has its value fetched.
Compare <a href="index.html#lvalue"><dfn>lvalue</dfn></a>.
See ANSI Sec. 3.2.2.1 (especially footnote 31)
or ISO Sec. 6.2.2.1.
(See also questions
<a href="../expr/qcolonlhs.html">3.16</a> and <a href="../ptrs/castincr.html">4.5</a>.)
</DD><DT><a name="scope">scope</a></DT>
<DD>n.
The region over which a declaration is active.

adj.
``In scope'': Visible.

See question <a href="../decl/namespace.html">1.29</a>.
</DD><DT><a name="semantics">semantics</a></DT>
<DD>n.
The meaning behind a program:
the interpretation which the compiler
(or other translator)
places on the various source code constructs.
Compare <a href="index.html#syntax"><dfn>syntax</dfn></a>.
</DD><DT><a name="short circuit">short circuit</a></DT>
<DD>v.
To prematurely terminate the evaluation of an expression
when the outcome is
determined.
The short-circuiting operators in C are <TT>&amp;&amp;</TT>, <TT>||</TT>,
and <TT>?:</TT>.
In the case of <TT>&amp;&amp;</TT> and <TT>||</TT>,
the second (right-hand) operand is not evaluated if the first one
determines the
outcome
(is zero in the case of <TT>&amp;&amp;</TT>,
or nonzero in the case of <TT>||</TT>).

In the case of <TT>?:</TT>, only one of the second and third
operands is evaluated,
depending on the value of the first operand.
See question <a href="../expr/shortcircuit.html">3.6</a>.
</DD><DT><a name="side effect">side effect</a></DT>
<DD>n.
Something
permanent
which happens
when an expression or subexpression is evaluated,
beyond
simply yielding a value.

Typical side effects are:
modifying a variable,

printing something.
See ANSI Sec. 2.1.2.3 or ISO Sec. 5.1.2.3.
</DD><DT><a name="sign preserving">sign preserving</a></DT>
<DD>adj.
Another name for the <a href="index.html#unsigned preserving"><dfn>unsigned preserving</dfn></a> rules, q.v.
</DD><DT><a name="source file">source file</a></DT>
<DD>n.
1.
Any file containing C source.
2.
More specifically,
a file with a name ending in .c,
containing function bodies and global variable definitions
(and perhaps declarations and definitions of other kinds).
Compare <a href="index.html#header file"><dfn>header file</dfn></a>, <a href="index.html#translation unit"><dfn>translation unit</dfn></a>.
See questions <a href="../decl/decldef.html">1.7</a> and <a href="../cpp/hfiles.html">10.6</a>.
</DD><DT><a name="Standard">Standard</a></DT>
<DD>(With a capital S:)
n.
The ANSI/ISO C Standard,
ANSI&nbsp;X3.159-1989 or ISO/IEC&nbsp;9899:1990
(see question <a href="../ansi/ansi1.html">11.1</a>).
adj.
Refers to something which is compatible with that Standard.
</DD><DT><a name="static">static</a></DT>
<DD>adj.
1.
(Often as ``static duration.'')
Refers to an object which persists throughout the lifetime of a program,
being allocated and initialized just once, at program startup.
Compare <a href="index.html#automatic"><dfn>automatic</dfn></a>.
See question <a href="../decl/initval.html">1.30</a>.
2.
Local to a source file,
i.e. not of global scope.
</DD><DT><a name="strictly conforming">strictly conforming</a></DT>
<DD>adj.
Refers to a program
which uses only the features described in the ANSI/ISO C Standard,
and does not depend on any
unspecified, undefined, or implementation-defined behavior.
(See ANSI Sec. 1.7 or ISO Sec. 4.)
</DD><DT><a name="string">string</a></DT>
<DD>n.
An array of <TT>char</TT>,
or a <TT>malloc</TT>'ed region,
containing a sequence of characters terminated with <TT>'\0'</TT>.
</DD><DT><a name="stringize">stringize</a></DT>
<DD>vt.
To convert a source token

into a string literal.

See questions
<a href="../ansi/stringize.html">11.17</a>
and
<a href="../ansi/macstrexp.html">11.18</a>.
</DD><DT><a name="string literal">string literal</a></DT>
<DD>n.
A sequence of characters between double quotes in source code.
Used to initialize an array of <TT>char</TT>,
or
to request an anonymous array
containing a constant string
(which will generally be accessed by
the pointer which the anonymous array decays to).
See question <a href="../decl/strlitinit.html">1.32</a>.
</DD><DT><a name="syntax">syntax</a></DT>
<DD>n.
The text of a program:
the
series
of tokens
in which it is expressed.
Compare <a href="index.html#semantics"><dfn>semantics</dfn></a>.
</DD><DT><a name="tag">tag</a></DT>
<DD>n.
The (optional) name for a particular
structure, union, or enumeration.

See question <a href="../struct/typedef.html">2.1</a>.
</DD><DT><a name="token">token</a></DT>
<DD>n.
1.
The smallest syntactic unit generally seen by a compiler or 
other translator:
a keyword, identifier, binary operator
(including multicharacter operators such as <TT>+=</TT> and <TT>&amp;&amp;</TT>),
etc.
2.
A whitespace-separated word within a string
(see question <a href="../lib/strtok.html">13.6</a>).
</DD><DT><a name="translation unit">translation unit</a></DT>
<DD>n.
The set of source files seen by the compiler and translated as a unit:
generally one .c file (that is, <a href="index.html#source file"><dfn>source file</dfn></a>, sense 2),
plus all header files mentioned in <TT>#include</TT> directives.
</DD><DT><a name="terminal driver">terminal driver</a></DT>
<DD>n.
That portion of the system software
responsible for character-based input and output,
usually interactive;
originally from and to a serially-connected terminal,
now more generally any virtual terminal
such as a window or network login session.
See question <a href="../osdep/cbreak.html">19.1</a>.
</DD><DT><a name="text">text</a></DT>
<DD>adj.
Refers to a file or I/O mode which is intended for handling 
human-readable text, specifically, printable characters

arranged into lines.
Compare <a href="index.html#binary"><dfn>binary</dfn></a>, sense 3.

See question
<a href="../stdio/textvsbinary.html">12.40</a>.
</DD><DT><a name="translator">translator</a></DT>
<DD>n.
A program
(compiler, interpreter, <TT>lint</TT>, etc.)
which parses and
interprets
semantic meaning in
C syntax.

</DD>


<DT><a name="unary">unary</a></DT>
<DD>adj.
Refers to an operator taking one operand.
Compare <a href="index.html#binary"><dfn>binary</dfn></a>,
sense 4.
</DD><DT><a name="undefined">undefined</a></DT>
<DD>adj.
Refers to behavior which is not specified by the Standard,
for which an implementation
is <em>not</em> required to do anything reasonable.

Example: the behavior of the expression <TT>i&nbsp;=&nbsp;i++</TT>.
See questions <a href="../expr/ieqiplusplus.html">3.3</a>
and <a href="../ansi/undef.html">11.33</a>.
</DD><DT><a name="unroll">unroll</a></DT>
<DD>vt.
To replicate the body of a loop one or more times
(while correspondingly reducing the number of iterations),
to improve efficiency
by reducing loop control overhead
(but at the expense of increased code size).
</DD><DT><a name="unsigned preserving">unsigned preserving</a></DT>
<DD>adj.
Refers to a set of rules,
common in pre-ANSI implementations,
for promoting
signed and unsigned types

which meet across binary operators,
and for promoting narrow unsigned types in general.
Under the unsigned preserving rules,
promotion
is always to an unsigned type.
Compare <a href="index.html#value preserving"><dfn>value preserving</dfn></a>.
See question <a href="../expr/preservingrules.html">3.19</a>.
</DD><DT><a name="unspecified">unspecified</a></DT>
<DD>adj.
Refers to behavior which is not fully specified by the Standard,
for which each implementation must choose some behavior,
though it need not be documented nor even consistent.

Example:
the order of evaluation of
function arguments and other subexpressions.
See question <a href="../ansi/undef.html">11.33</a>.
</DD><DT><a name="value preserving">value preserving</a></DT>
<DD>adj.
Refers to a set of rules,
mandated by the ANSI C Standard
and also
present in some pre-ANSI implementations,
for promoting
signed and unsigned types

which meet across binary operators,
and for promoting narrow unsigned types in general.
Under the value preserving rules,
promotion is to a signed type
if it is large enough to preserve all values,
otherwise to an unsigned type.
Compare <a href="index.html#unsigned preserving"><dfn>unsigned preserving</dfn></a>.
See question <a href="../expr/preservingrules.html">3.19</a>.
</DD><DT><a name="varargs">varargs</a></DT>
<DD>adj.
1.
Refers to a function which accepts a variable number of
arguments,
e.g. <TT>printf</TT>.
(A synonym for <a href="index.html#variadic"><dfn>variadic</dfn></a>.)
2.
Refers to one of the arguments
in the variable-length part of a variable-length argument list.
</DD><DT><a name="variadic">variadic</a></DT>
<DD>adj.
Refers to a function which accepts a variable number of
arguments,
e.g. <TT>printf</TT>.
(A synonym for <a href="index.html#varargs"><dfn>varargs</dfn></a>, sense 1.)
</DD><DT><a name="wrapper">wrapper</a></DT>
<DD>n.
A function
(or macro)
which is ``wrapped around'' another,
providing a bit of added functionality.
For example, a wrapper around <TT>malloc</TT>
might check <TT>malloc</TT>'s return value.
</DD><DT><a name="X3.159">X3.159</a></DT>
<DD>n.
The original ANSI C Standard,
ANSI X3.159-1989.
See question <a href="../ansi/ansi1.html">11.1</a>.
</DD><DT><a name="X3J11">X3J11</a></DT>
<DD>n.
The committee charged by ANSI with the task of drafting the C Standard.



X3J11 now functions as the US Technical Advisory Group
to the ISO C standardization working group WG14.
See question <a href="../ansi/ansi1.html">11.1</a>.
</DD></DL><hr>
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