- R
-
- redirect
- To associate files with the input or output of commands.
- reentrant
- The attribute of a program or routine that allows the same copy of a program or routine
to be used concurrently by two or more tasks.
- reference class
- A class that links a concrete class to an abstract class. Reference classes make
polymorphism possible with the collection classes. See abstract
class, concrete class, polymorphism.
- reference counted object
- an object that keeps track of the number of pointers that refer to it. This number is
called the reference count. See reference
counting.
- reference counting
- The technique of keeping track of how many pointers refer to a given object. See reference counted object and counted pointer.
- register
- A storage area commonly associated with fast-access storage, capable of storing a
specified amount of data such as a bit or address.
- register storage class specifier
- A specifier that indicates to the compiler within a block scope data definition or a
parameter declaration that the object being described will be heavily used.
- register variable
- A variable defined with the register storage class specifier. Register variables have
automatic storage.
- regular expression
- (1) A mechanism to select specific strings from a set of character strings. (2) A set of
characters, metacharacters, and operators that define a string or group of strings in a
search pattern. (3) A string containing wildcard characters and operations that define a
set of one or more possible strings.
- regular file
- A file that is a randomly accessible sequence of bytes, with no further structure
imposed by the system. X/Open, I.
- relation
- An unordered flat collection class that uses keys, allows for duplicate elements, and
has element equality. See key access, unordered collection.
- relational database
- (1) A data structure organized so that it is perceived by its users as a collection of
tables. (2) A database that is organized and accessed according to relations. T. A
relational database has the flexibility to generate new tables from existing records that
meet specified criteria.
- renderer
- An object that renders data using a particular mechanism, such as using files or shared
memory. It contains definitions of supported rendering mechanisms and formats and types.
- rendering
- (1) The transfer or re-creation of the dragged object from the source window to the
target window.
- resource
- (1) Any facility of a computing system or operating system required by a job or task,
including main storage, input/output devices, the processing unit, data sets, and control
or processing programs. (2) A binary data item that is linked to an executable file, a
DLL, or some other binary file. Typically a resource defines an interface component such
as a dialog box, a menu, an icon, a font, a bitmap, or a cursor. (3) Any element that
requires translation, such as messages or online help.
- resource file
- A source file or compiled file that defines the resources that are used by an
application. VisualAge C++ recognizes uncompiled resource files by the file extension .rc.
A compiled resource file has the file extension .res.
- response file
- A file that acts as an extension of command-line input, providing options and parameters
as input to a component.
- return
- A language construct that ends an execution sequence in a procedure. IBM.
- return value
- A scalar returned by a function that does not have type void.
- REXX
- Restructured Extended Executor. An IBM structured programming language used as a
general-purpose macro language that sends commands to application programs and to the
operating system.
- RGB
- Red, green, blue. A method of processing color images according to their red, green, and
blue color content.
- RMFs
- Rendering mechanisms and formats.
- root
- In a tree structure, a node that has no parent. All other nodes of a tree are
descendants of the root. See tree, node,
child node, parent node.
- RTTI
- See run-time type identification.
- run-time library
- A compiled collection of functions whose members can be referred to by an application
program during run-time execution. VisualAge C++ contains separate run-time libraries for
C and C++.
- run-time type identification (RTTI)
- A mechanism in the C++ language for determining the class of an object at run time. It
consists of two operators: one for determining the run-time type of an object (typeid),
and one for doing type conversions that are checked at run time (dynamic_cast). A
type_info class describes the RTTI available and defines the type returned by the typeid
operator.
- rvalue
- (1) An expression that must appear on the right side of an assignment. (2) An expression
that cannot have a value assigned to it. The result of calling a function that does not
return a reference. Rvalues always have complete types or the void type. Contrast with lvalue.
