Polymorphic Data Structures in C/Glossary

A

Address

The location in memory where a variable is stored.

Address-of Operator

The ampersand (&), used to reference a variable's address instead of its value.

Argument

A variable passed to a function. The term argument is generally reserved for variables passed to main() at runtime, usually from the command line interface; see parameter.

D

Dereference Operator

The asterisk (*), used to access the value that a pointer points to as opposed to the pointer itself.

Dereference-Member Operator

A hyphen, followed by a greater-than sign (->), used to access the members of a union or structure through a pointer to that construct.

G

Global Variable

A variable declared independently of a function. Global variables are accessible anywhere in a program.

L

Local Variable

A variable declared in a function's definition. Local variables can only be used in the function that declared them.

M

Member Operator

The period (.), used to access members of a union or structure.

P

Parameter

An argument passed to a function for processing. Parameters are not changed in the calling function, but rather they are copied and stored locally in the called function's runtime stack.

Pointer

A variable that stores the address of another variable, eg. a variable that "points" to a value.

S

Static Variable

A variable declared inside a function. Static variables can only be used in the function that declared them.

String

A sequence of characters terminated with a null byte. Represented in C as an array of chars, where the length is at least ( string_length + 1 ) to account for the null byte.

T

Type

See variable type.

V

Variable

A symbolic name given to a value with a known or unknown quantity. Variables always have type.

Variable Type

The way that the compiler interprets the bits stored at a variable, eg. what kind of data is stored and referenced by a variable.