Glossary R

Visual Studio 6.0

r-value

The value on the right side of an expression. R-values are sometimes used to describe the value of the expression and to distinguish it from an l-value. An r-value can be one or more of the following: variable, constant, literal, mathematical expression, or function. See also l-value.

radio button

Or option button. In graphical user interfaces, a round button operated by the user to toggle an option or choose from a set of related but mutually exclusive options. The radio button has two states, selected (or checked) and cleared (or unchecked). When selected, a black dot appears inside the button's circle. See also radio group.

radio group

A number of radio buttons grouped together in a group-box control. A radio group allows the user to choose from a set of mutually exclusive options; selecting one radio button automatically clears the previously selected button.

radix

  1. The number base for numeric input and displayed output. Visual C++ allows octal (8), hexadecimal (16), and decimal (10) radixes. The default radix is decimal.

  2. In SQL, a column that identifies numeric data types; possible values are 10, 2, or NULL.

RAM

Semiconductor-based memory that can be read from and written to by the microprocessor or other hardware devices. The storage locations can be accessed in any order (i.e., randomly). While other types of memory, including read-only memory (ROM), can also be accessed randomly, RAM is generally understood to refer to volatile memory that can be written to as well as read.

random access memory

Semiconductor-based memory that can be read from and written to by the microprocessor or other hardware devices. The storage locations can be accessed in any order (i.e., randomly). While other types of memory, including read-only memory (ROM), can also be accessed randomly, RAM is generally understood to refer to volatile memory that can be written to as well as read.

RAS

A Windows NT Server feature by which a single serial connection provides a remote workstation with host connectivity, NT file services, or Novell file and printing services (NWLink).

raster

A horizontal line of pixels. A raster display device creates images composed of pixels, or dots. Computer monitors and laser printers are examples of raster devices. Devices such as plotters, which create images on paper by drawing lines with a pen, are not raster devices.

raster display

A video monitor that displays an image on the screen from top to bottom as a series of horizontal scan lines. The scan lines are as wide as the smallest visible image on the screen. Within each scan line, individual picture elements, or pixels, can be illuminated. Television screens and most computer monitors are raster displays.

raster font

Or bitmap font, nonscalable font. A font in which each glyph (character or symbol) is of a particular size and style, designed for a specific resolution of device and described as a unique bitmap. See also scalable font, TrueType font, vector font.

raster operation

In computer graphics, a Boolean operation that combines either the values of the pixels in the selected pen and the destination bitmap (binary operation) or the values of the pixels in the source, the selected brush, and the destination (ternary operation). See also raster operation code.

raster operation code

A 32-bit code that defines how Windows combines colors in output operations that involve a current brush, a possible source bitmap, and a destination bitmap. See also raster operation (ROP).

rasterization

The conversion of vector graphics to equivalent images composed of pixel patterns that can be stored and manipulated as sets of bits. See also raster operation (ROP).

raw data

Unprocessed, typically unformatted data. Raw data is a stream of bits that has not been filtered for commands or special characters. More generally, it is information that has been collected but not evaluated.

read-only

Describes information stored in such a way that it can be played back (read) but cannot be changed (written). See also write-only.

record

  1. (noun) A collection of data about a single entity, such as an account or a customer, stored in a row of a table. A record consists of a group of contiguous columns (sometimes called "fields") that contain data of various types. See also recordset.

  2. (verb) To retain information, usually in a file.

record field exchange

When bulk row fetching is not implemented, the mechanism by which MFC ODBC classes transfer data between the field data members of a recordset object and the corresponding columns of an external data source. See also bulk record field exchange (Bulk RFX), dialog data exchange (DDX), DAO record field exchange (DFX).

record view

In form-based data-access applications, a form view object whose controls are mapped directly to the field data members of a recordset object and indirectly to the corresponding columns in a query result or table on the data source. See also form view, recordset.

recordset

A set of records selected from a data source. The records can be from a table, a query, or a stored procedure that accesses one or more tables. A recordset can join two or more tables from the same data source, but not from different data sources. See also dynaset, result set, snapshot.

recordset object

In MFC, an instance of class CRecordset or class CDaoRecordset, or an instance of any class derived from these. See also record field exchange (RFX).

recursive

The ability of a function or a routine to call itself.

red, green, blue

Or RGB values, RGB color. A mixing model, or method of describing colors, in light-based media such as color monitors. RGB mixes percentages of the light-based primary colors (red, green, and blue) to create other colors. Windows defines these percentages as three 8-bit values called RGB values. Zero percentage of all three primaries, or an RGB value of (0,0,0), produces black and 100 percent of all three primaries, or an RGB value of (255,255,255), produces white. See also red, green, blue, alpha (RGBA).

red, green, blue, alpha

A model that augments the red, green, blue (RGB) method of combining colors in light-based media, with a fourth color component, alpha, which is used to control color blending. In Open GL, an alpha value of 1.0 corresponds to complete opacity and a value of 0.0 corresponds to complete transparency. See also red, green, blue (RGB).

redraw flag

A Boolean parameter to many Windows functions which, when cleared, prevents the content of the given window from being updated (redrawn). When set, this flag allows the window to be repainted with new information.

Reduced Instruction Set Computer

A computer based on a high-speed processing technology that uses a reduced set of operating commands compared with Complex Instruction Set Computers. RISC speeds performance for calculation-intensive procedures by doing the most common operations quickly.

reentrant

Code written so that it can be shared by several programs (or processes within a single program) at the same time. When code is reentrant, one program or process can safely interrupt the execution of another program or process, execute its own code, and then return control to the first program or process in such a way that the first program or process does not fail or behave in an unexpected way.

reference

  1. (noun) In C++, a form of pointer that can be used to access a variable by its address. When such a reference is declared, it must be associated with a variable. The reference becomes an alias for that variable. See also address-of (&) operator.

  2. (verb) To access a variable, often said of elements in an array or in a record.

reference count

A count of the number of pointers that access, or make reference to, an object, allowing for multiple references to a single object. This number is decremented when a reference is removed; when the count reaches zero, the object's space in memory is freed.

reference counting

A running count of the number of clients of a resource. A reference count implements garbage collection, and also ensures that an object is not destroyed before all references to it are released.

referential integrity

In database management, a set of rules that preserves the defined relationships between tables when records are entered or deleted. Enforcing referential integrity would, for example, prevent a record from being added to a related table when there is no associated record in the primary table. See also schema.

region

  1. In Windows-based applications, a rectangle, polygon, ellipse, or combination of two or more of these shapes used to define a part of the client window to be painted, inverted, filled with output, framed, or used for hit testing.

  2. More generally, an area dedicated to, or reserved for, a particular purpose.

register

  1. (noun) A small (typically 32-bit), named region of high-speed memory located within the microprocessor and used as a holding area for specific, sometimes critical, pieces of data related to activities going on within the system. For example, a register might be used to hold the results of an addition operation or to hold the address of a particular location in the computer's memory. See also register variable.

  2. (verb) The process whereby an application or thread provides information about itself in a registration database or with a registration class. For example, an OLE server application registers with the OLE system registration database. See also registry.

register storage class

A declaration for function arguments and local variables requesting that the associated values be held in high-speed memory registers, if these registers are available. This storage class defaults to automatic when register storage is not possible. The Visual C++ compiler does not honor user requests for register variables; instead, it makes its own register choices when global opitimizations are on. However, the compiler does honor all other semantics associated with the register keyword when this declaration is used. See also automatic storage class, static storage class.

register variable

In C/C++, a local variable that a program specifies to be stored in a high-speed memory register, if possible, using the keyword register. See also register storage class.

registration entry file

In OLE applications, a text file description of the classes supported by a server application. When a server application is installed in a system, the contents of its registration entry file are merged with the system registry. Registration entry files usually have a .REG filename extension.

registry

Or OLE system registry, Windows NT registry, system registration database. In 32-bit Windows, the database in which configuration information is registered. This database takes the place of most configuration and initialization files for Windows and new Windows-based applications. See also  registration entry file.

registry key

A unique identifier assigned to each piece of information in the system registration database.

regular expression

A search string that uses special characters to match a text pattern in a file. For example, an asterisk (*) means "zero or more occurrences of the preceding character"; thus, ab*c matches ac, abc, abbc, abbbc, etc.

relational database

A type of database or database management system that stores information in tables–rows and columns of data–and conducts searches by using data in specified columns of one table to find additional data in another table.

relative link

Links that keep the hyperlink intact even if you move the file containing the hyperlink.

relative path

The location of a file, document, or other object as it relates to the current location. The relative path to a target object includes only that portion of the path that is different from the path of the source object. For example, the relative path from c:\animal\mammal\canine\fido to c:\animal\mammal\feline\fluffy is ..\ ..\feline\fluffy. See also fully qualified path.

relative time

Or time span. The difference between two absolute time values.

release version

A compiled version of a program that does not include the debugging and diagnostic features included in a build compiled in debug mode. For example, a release version will not include the source code contained in  ASSERT macros. See also debug version.

relocation information

Information that tells the linker what instructions in the object file will need to be "patched" with addresses of other objects defined in other source files. Those addresses will be known when all the object files are linked together.

Remote Access Service

A Windows NT Server feature by which a single serial connection provides a remote workstation with host connectivity, NT file services, or Novell file and printing services (NWLink).

remote debugging

  1. To debug an application written for, and running on, a platform other than the one on which you are running Visual C++ (the host machine). The remote machine is connected to the host machine through the serial port or, in the case of a Macintosh, an AppleTalk network connection. See also debug monitor.

  2. More generally, to debug an application that is running on a computer other than the one on which the debugger resides.

remote machine

  1. In the case of remote debugging, the machine on which the target application (the one being debugged) is running, as opposed to the host machine, which is running the debugger. See also debug monitor.

  2. Or remote computer. More generally, any computer that is not in the immediate vicinity, but which is accessible through some type of cable or communications link. See also local machine.

Remote Procedure Call

A widely used standard defined by the Open Software Foundation (OSF) for distributed computing. RPC enables one process to make calls to functions that are part of another process. The other process can be on the same computer or on a different computer on the network.

remote server

A server application, implemented as an executable file, that runs on a different machine from the client application using it. See also in-process server, local server.

repeat count

A value specifying the number of times a keystroke is repeated as a result of the user holding down the key.

reserve size

The amount of a resource that is to be allocated (or "committed") for a particular use. For example, in the header of a COFF file, the Windows NT–specific field Heap Commit Size specifies the size of the local heap that the linker and loader are to reserve for that file. Only the commit size is initially allocated; the rest is made available one page at a time, until the reserve size is reached.

resource

  1. A program block, dialog box template, bitmap, font, or sound, for example, that can be used by more than one program or in more than one place in a program. The use of resources allows alteration of many features in a program without the necessity of recompiling the program from source code. See also resource type.

  2. More generally, any part of a computer system or a network that can be allotted to a program or a process while it is running.

resource browser window

A window that displays the resources associated with a project. From the resource browser window, an application's resources can be added, deleted, or changed.

resource compiler

An application that creates a binary resource file based on the resource-definition (.RC) file. The resource compiler can also append binary resource data to an executable file and create a resource table in the executable file's header.

resource editor

A specialized utility program that can be used to add, edit and delete program resources.

resource fork

The portion of an Apple Macintosh file containing reusable items of information that the program can use during execution, such as blocks of code, icons, fonts, and digitized sounds. See also data fork.

resource identifier (ID)

In Microsoft Windows and in the Apple Macintosh Operating System, a number that identifies a particular resource within a given resource type — for example, a particular menu among many resources of type MENU that a program can use. The resource type, along with the resource ID, uniquely defines every resource in an application. (Note that resources of different types can have the same resource ID.)

resource type

A category of structural or procedural resources in Microsoft Windows and in the Apple Macintosh Operating System, such as code, fonts, dialog boxes, or icons. The resource type, along with the resource ID, uniquely defines every resource in an application.

resource-definition file

Or resource script file. A text file containing descriptions of resources from which the resource compiler creates a binary resource file. For Microsoft Windows applications, resource-definition files usually have a .RC filename extension. For Apple Macintosh applications, such files are typically named with a .R extension and written with the Apple Rez script language. See also compiled resource file.

RESOURCE.H file

The default name for the header file that corresponds to an application's resource-definition file.

response file

A text file that can contain multiple options and filenames that would otherwise be typed on the command line or specified by using the CL environment variable. The options in the response file are interpreted as if they were present on the command line at the position of the response file invocation.

restored window

A window that has been returned to its preminimized or premaximized size and position.

result set

A collection of data returned by an SQL query on a database. A Known result set is when the database application knows the exact form of the SQL statements and, therefore, the form of the result set, at compile time. An Unknown result set is when the application does not know the exact form of the SQL statement at compile time and, therefore, cannot predict the format of these results prior to execution. See also recordset.

return code

Or result code, exit code. A predefined code used to report the outcome of a procedure or to influence subsequent events when a routine or process terminates (returns) and passes control of the system to another routine. The return code can indicate success or failure, or can even indicate a particular type of failure that is within the normal range of expectations. For example, the exception-handling functions in C++ generate return codes.

return type

The data type returned by a function. The type-specifier field of a function definition can specify any fundamental, class, structure, or union type, or void.

return value

The value that a function evaluates to in its calling expression.

Rez

A script language that is part of the Macintosh Programmer’s Workshop and is used to specify the resources to be used by a Macintosh applicaton. MRC.EXE, the Macintosh Resource Compiler, provides a Windows NT implementation of Rez.

RFX

When bulk row fetching is not implemented, the mechanism by which MFC ODBC classes transfer data between the field data members of a recordset object and the corresponding columns of an external data source. See also bulk record field exchange (Bulk RFX), dialog data exchange (DDX), DAO record field exchange (DFX).

RGB

A mixing model, or method of describing colors, in light-based media such as color monitors. RGB mixes percentages of the light-based primary colors (red, green, and blue) to create other colors. Windows defines these percentages as three 8-bit values called RGB values. Zero percentage of all three primaries, or an RGB value of (0,0,0), produces black and 100 percent of all three primaries, or an RGB value of (255,255,255), produces white. See also red, green, blue, alpha (RGBA).

RGBA

A model that augments the red, green, blue (RGB) method of combining colors in light-based media, with a fourth color component, alpha, which is used to control color blending. In Open GL, an alpha value of 1.0 corresponds to complete opacity and a value of 0.0 corresponds to complete transparency. See also red, green, blue (RGB).

RGBA mode

In OpenGL, a color pixel data mode. An OpenGL context is in RGBA mode if its color buffers store red, green, blue, and alpha color components instead of color indexes.

rich edit control

In MFC, a window in which the user can enter and edit text. The text can be assigned character and paragraph formatting and can include embedded OLE objects.

rich-text format file

A file that contains encoded, formatted text and graphics for easy transfer between applications. The rich-text encoding format is commonly used by document-processing programs such as Microsoft Word for Windows and for generating online Help files. Rich-text format files usually have a .RTF filename extension.

right outer join

A database term that describes the relationship between two tables on which a query is run. If two tables are connected with a right outer join, the resulting recordset contains all records from the table on the right but only those records from the table on the left where the joined fields are equal. See also left outer join.

RISC

A computer based on a high-speed processing technology that uses a reduced set of operating commands compared with Complex Instruction Set Computers. RISC speeds performance for calculation-intensive procedures by doing the most common operations quickly.

risk management

The total process of identifying, controlling, and eliminating or minimizing the effects of uncertain events, such as power failures or hacker activity, that may affect system resources. It includes risk analysis, cost benefit analysis, selection, implementation and test, security evaluation of safeguards, and overall security review.

RLE8 compression

An image compression format for device-independent bitmaps that encodes a sequence of identical pixels as a repeat count and a color value.

rollback

A database operation that allows recovery from changes made during a transaction that was canceled or failed. Rollback returns the records to the state they were in as of the last commit (saved transaction).

root

In a hierarchy of items, the one item from which all other items are descended. The root item has nothing above it in the hierarchy. See also inheritance hierarchy.

root storage object

The outermost storage object of a storage hierarchy. A root storage object can contain other nested storage and stream objects. For example, a compound document is saved on disk as a series of storage and stream objects within a root storage object. See also compound document, storage object, stream object.

ROP

In computer graphics, a Boolean operation that combines either the values of the pixels in the selected pen and the destination bitmap (binary operation) or the values of the pixels in the source, the selected brush, and the destination (ternary operation). See also raster operation code.

ROT

A globally accessible table on every computer that tracks the OLE objects that can be identified by a moniker and are currently running on the local computer. Monikers use the running object table. Registering an object in the running object table increments the object's reference count. Before the object can be destroyed, its moniker must be released from the running object table.

rotation

A transformation that makes a displayed graphical object appear to have been turned (rotated) in space, relative to the coordinate-space origin.

router

A hardware device that connects two or more networks, or connects a network to the Internet. It converts addresses and sends on only those messages that need to pass to the other network.

rowset

In ODBC, one or more rows returned by a single fetch operation.

RPC

A widely used standard defined by the Open Software Foundation (OSF) for distributed computing. RPC enables one process to make calls to functions that are part of another process. The other process can be on the same computer or on a different computer on the network.

RTTI

In C++, a mechanism that allows the type of an object to be determined during program execution.

RTTI

Run-time type information. A mechanism that allows the type of an object to be determined during program execution. Compare with type information.

rubber-band selection

A selection method that allows a user to select multiple items by dragging a sizing rectangle around the items to be selected. Items within the region can be manipulated by the user. For instance, the user might drag or drop the selection into another container application.

run time

The point in time when a program is running, or the period of time needed to execute the program. See also compile time, link time.

run-time class information

Information about an object's class accessed at run time. This information is useful for doing extra type-checking or creating dynamic objects at run time. Classes derived from the MFC class CObject can have this functionality. See also run-time type information (RTTI).

run-time error

A math or logic error in a program that becomes apparent only at run time. Such an error may produce incorrect results or cause the program to behave unpredictably or crash.

run-time property

Discrete state information associated with a control object or its container. There are three types of run-time properties: ambient properties, control properties, and extended properties. Contrast with persistent property.

run-time type information

In C++, a mechanism that allows the type of an object to be determined during program execution.

run-time type information

A mechanism that allows the type of an object to be determined during program execution. Compare with type information.

Running Object Table

A globally accessible table on every computer that tracks the OLE objects that can be identified by a moniker and are currently running on the local computer. Monikers use the running object table. Registering an object in the running object table increments the object's reference count. Before the object can be destroyed, its moniker must be released from the running object table.

running state

In OLE, the status of a compound document object (either a linked or embedded item) when the object's application is running and it is possible to edit the object, access its interfaces, and receive notification of changes. See also loaded state.

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