C
 
call
To transfer control to a procedure, program, routine, or subroutine. IBM.
caller
A routine that calls another routine.
Call Level Interface (CLI)
A callable C-language API for database access, which offers an alternative to an embedded SQL API.
canvas
A window with a layout algorithm that manages child windows.
carriage-return character
A character that in the output stream indicates that printing should start at the beginning of the same physical line in which the carriage-return character occurred. The carriage-return is the character designated by '\r' in the C and C++ languages. It is unspecified whether this character is the exact sequence transmitted to an output device by the system to accomplish the movement to the beginning of the line. X/Open.
case clause
In a switch statement, a case label followed by any number of statements.
case label
The word case followed by a constant expression and a colon. When the selector evaluates the value of the constant expression, the statements following the label are processed.
cast
A notation used to express the conversion of one type to another. It can be expressed using either functional notation or cast notation, or (in C++) one of the following type conversion operators: const_cast,
reinterpret_cast, dynamic_cast, static_cast.
cast expression
An expression that explicitly converts its operand to a specified arithmetic, scalar, or class type.
cast operator
An operator used for specific type conversions.
catch block
A block associated with a try block that receives control when a C++ exception matching its argument is thrown.
CD-XA
See compact disc-extended architecture.
CECP
See country extended code page.
channel mapping
The translation of a MIDI channel number for a sending device to an appropriate channel for a receiving device.
character
(1) A letter, digit, or other symbol that is used to represent data. (2) A sequence of one or more bytes representing a single graphic symbol or control code. This term corresponds to the ISO C standard term multibyte character, where a single-byte character is a special case of the multibyte character. Unlike the usage in the ISO C standard, character here has no necessary relationship with storage space, and byte is used when storage space is discussed. X/Open, I. See multibyte character.
character array
An array of type char. X/Open.
character class
A named set of characters sharing an attribute associated with the name of the class. The classes and the characters that they contain are dependent on the value of the LC_CTYPE category in the current locale. X/Open.
character constant
A character or an escape sequence enclosed in apostrophes.
character set
(1) A finite set of different characters that is complete for a given purpose; for example, the character set in ISO Standard 646, 7-bit Coded Character Set for Information Processing Interchange. T. See single-byte character set, double-byte character set, basic source character set, portable character set. (2) All the valid characters for a programming language or for a computer system. IBM. (3) A group of characters used for a specific reason; for example, the set of characters a printer can print. IBM.
character string
A contiguous sequence of characters terminated by and including the first null byte. X/Open.
character variable
The name of a character data item whose value is assigned or changed during program execution. IBM. See variable.
checkpoint
(1) A sequence of instructions in a computer program for recording the status of execution for restarting. T. (2) A point at which information about the status of a job and the system can be recorded so that the job step can be later restarted. IBM.
child class
See derived class.
child node
In a tree structure, a node that is subordinate to another node. Only the root node of a tree is not a child. See parent node, root.
child window
A window derived from another window and drawn relative to it. See parent window.
circular slider control
A 360-degree knob-like control that simulates the rotating knobs on a TV or a stereo. By rotating the slider arm, the user can set, display, or modify a value, such as the volume, balance, bass, or treble.
class
(1) A group of objects that share a common definition and that therefore share common properties, operations, and behavior. (2) (C++ only) A user-defined type that is defined with the class-key 'class,' 'struct,' or 'union.' Objects of a class type consist of zero or more members and base class objects. See member. Classes can be defined hierarchically, allowing one class to be an expansion of another, and classes can restrict access to their members.
class hierarchy
A base class and all of the classes derived from it.
class identifier (CLSID)
In the Win32 API, the globally unique identifier for an object. The Win32 system registration database uses the CLSID to distinguish all OLE objects available on a system. A CLSID is a 16-byte value that contains 32 hexadecimal digits. Also commonly referred to as a globally unique identifier (GUID).
class key
Any of these three C++ keywords: class, struct, or union.
class library
One or more class hierarchies that have been defined to fulfill a specific purpose or number of purposes.
class name
(C++ only) An arbitrarily long sequence of letters and digits that uniquely identifies a class.
class scope
That part of a source program that defines class member names. A name declared in a class member is hidden within the scope of the class. See scope. Contrast with global scope, local scope, namespace scope.
class tag
See class name.
class template
A template that results in the creation of a class type when it is implicitly or explicitly instantiated or specialized. See template class, template.
CLI
Call Level Interface.
C library
A system library that contains common C language subroutines for file access, string operators, character operations, memory allocation, and other functions. IBM.
C++ library
A system library that contains common C++ language subroutines for file access, memory allocation, and other functions. See class library.
client
(1) A functional unit that receives shared services from a server. T. (2) In an AIX distributed file system environment, a system that is dependent on a server to provide it with programs or access to programs. Contrast with server.
client code
A C++ program that uses a class. The program is said to be a client of the class.
CLSID
Class identifier.
coded character set
(1) A set of graphic characters and their code point assignments. The set may contain fewer characters than the total number of possible characters: some code points may be unassigned. IBM. (2) A coded set whose elements are single characters; for example, all characters of an alphabet. T.
coded character set identifier (CCSID)
A 16-bit number constituting a set of encoding scheme identifiers, character set identifiers, code page identifiers, and additional information that uniquely identifies a coded graphic character representation.
code page
(1) An assignment of graphic characters and control function meanings to all code points; for example, assignment of characters and meanings to 256 code points for an 8-bit code, or assignment of characters and meanings to 128 code points for a 7-bit code. (2) A particular assignment of hexadecimal identifiers to graphic characters.
code point
(1) A unique code assigned to graphic characters in a code page. (2) A 1-byte code representing 1 of 256 possible characters. Within a code page, a code point can have only one specific meaning. (3) An identifier in an alert description that represents a short unit of text. The code point is replaced with the text by an alert display program.
collating element
The smallest entity used to determine the logical ordering of character or wide-character strings. A collating element consists of either a single character, or two or more characters collating as a single entity. The value of the LC_COLLATE category in the current locale determines the current set of collating elements. X/Open. VisualAge C++ uses collating elements when processing strings for regular expressions, pattern matching, and sorting.
collating sequence
(1) A specified arrangement used in sequencing. I, ANSI. (2) An ordering assigned to a set of items, such that any two sets in that assigned order can be collated. ANSI. (3) The relative ordering of collating elements as determined by the setting of the LC_COLLATE category in the current locale. The character order, as defined for the LC_COLLATE category in the current locale, defines the relative order of all collating elements, such that each element occupies a unique position in the order. This is the order used in ranges of characters and collating elements in regular expressions and pattern matching. In addition, the definition of the collating weights of characters and collating elements uses collating elements to represent their respective positions within the collation sequence.
collation
The logical ordering of character or wide-character strings according to defined precedence rules. These rules identify a collation sequence between the collating elements, and such additional rules that can be used to order strings consisting of multiple collating elements. X/Open.
collection
(1) An implementation of an abstract data type for storing elements. (2) An abstract class without any ordering, element properties, or key properties.
collection classes
A set of classes that implement abstract data types for storing elements.
column
(1) A vertical arrangement of data. (2) In a relational database, the vertical component of a table. A column has a name, an indication of whether it is nullable, and a particular data type, for example character or integer.
comma expression
An expression that contains two operands separated by a comma. Although the compiler evaluates both operands, the value of the expression is the value of the right operand. If the left operand produces a value, the compiler discards this value. Typically, the left operand of a comma expression is used to produce side-effects.
command
An instruction to perform an operation or run a program. When parameters, arguments, flags, or other operands are associated with a command, the resulting character string is a single command.
command line interface
A type of computer interface in which the input command is a string of text. Contrast with graphical user interface (GUI).
common controls
In the Windows operating system, a DLL that includes the following: header control (a window for displaying multiple columns of data), list view (a way to display objects as icons with labels), progress bar, property sheet, status bar, tool bar, track bar (slider control), tree view (an outline-type list), and an up-down control (spin control).
compact disc-extended architecture (CD-EX)
A storage format that accommodates interleaved storage of audio, video, and standard file system data.
compact disc-read-only memory (CD-ROM)
High-capacity, read-only memory in the form of an optically read compact disc.
compilation unit
A portion of a computer program sufficiently complete to be compiled correctly. IBM. See translation unit.
compile
To translate from source code into an object form.
compiler listing
See listing.
compiler options
Keywords that can be specified to control certain aspects of compilation.
complete class name
The complete qualification of a nested class name, including all enclosing class names.
Complex Mathematics library
A C++ class library that provides the facilities to manipulate complex numbers and perform standard mathematical operations on them.
composite
The combination of two or more film, video, or electronic images into a single frame or display.
compound document
A means for integrating arbitrary or unstructured data from different sources into one centralized location.
Compound Document Framework
A set of classes that can be used to create a server or container document component that is OLE-enabled. The framework stores compound documents using the OLE-structured storage specification (docfiles).
computer-controlled device
An external video source device with frame-stepping capability, usually a videodisc player, whose output can be controlled by the multimedia subsystem.
concrete class
A class that can be instantiated to produce objectss of that class. See polymorphism, reference class. Contrast with abstract class.
condition
(1) A relational expression that can be evaluated to a value of either true or false. IBM. (2) An exception that has been enabled, or recognized, by the language environment and thus is eligible to activate user and language condition handlers. (3) Any alteration to the normal programmed flow of an application. Conditions can be detected by the hardware or operating system and result in an interrupt. They can also be detected by language-specific generated code or language library code.
conditional compilation directive
See conditional inclusion preprocessor directive.
conditional expression
A compound expression that contains a condition (the first expression), an expression to be evaluated if the condition has a nonzero value (the second expression), and an expression to be evaluated if the condition has the value zero (the third expression).
conditional inclusion preprocessor directive
A preprocessor directive that causes the preprocessor to process specified source code in the file depending on the evaluation of a specific condition.
connection
A formal, explicit relationship among parts. Connections define the way parts communicate with each other. See custom logic connection.
const
(1) An attribute of a data object that declares that the value of the object cannot be changed. (2) An attribute of a member function that declares that the function will not modify data members of its class.
constant
(1) In programming languages, a language object that takes only one specific value. I. (2) A data item with a value that does not change during the running of the program. (3) Having a value that can be determined during compilation and that does not change during the running of the program.
constructor
In C++, a special class member function that is used to initialize objects of its class type. A return type is not specified. See default constructor and destructor.
container
An object that holds other objects. IBM. Containers can also be servers and can therefore be embedded inside other containers. A container can hold zero or more embedded components.
containment function
A function that determines whether a collection contains a given element.
control
A graphic object that represents operations or properties of other objects. See tree control.
control character
(1) A character whose occurrence in a particular context specifies a control function. T. (2) A character, other than a graphic character, that affects the recording, processing, transmission, or interpretation of text. X/Open. See nonprinting character.
control program
(1) A computer program designed to schedule and to supervise the execution of programs of a computer system. I. A. (2) The part of the AIX Base Operating System that determines the order in which basic functions should be performed. IBM.
control statement
A language statement that changes the normal path of execution.
conversion
(1) In programming languages, the transformation between values that represent the same data item but belong to different data types. Information may be lost because of conversion since accuracy of data representation varies among different data types. I. (2) The process of changing from one method of data processing to another or from one data processing system to another. IBM. (3) The process of changing from one form of representation to another; for example, changing from decimal representation to binary representation. IBM. (4) A change in the type of a value; for example, when you add values having different data types, the compiler converts both values to a common form before adding the values.
conversion function
A member function that specifies a conversion from its class type to another type.
Coordinated Universal Time (UTC)
The international standard of time, kept by atomic clocks around the world.
copy constructor
A constructor used to make a copy of an object from another object of the same type.
counted pointer
An object that behaves like a C++ pointer that you use for reference counting.
country extended code page
A single-byte EBCDIC coded character set in the IBM corporate registry. Each code page contains the same character set, with an identifier of 00697 (also known as Latin Alphabet Number 1), but pages differ in their code point allocations.
current working directory
(1) A directory, associated with a process, that is used in path-name resolution for path names that do not begin with a slash. X/Open, I. (2) In DOS, the directory that is searched when a file name is entered with no indication of the directory that lists the file name. DOS assumes that the current directory is the root directory unless a path to another directory is specified. IBM. (3) In the AIX operating system, a directory that is active and that can be displayed. Relative path name resolution begins in the current directory. IBM.
cursor
(1) A reference to an element at a specific position in a data structure. (2) A database control structure used to point to a specific row within some ordered set of rows, and to retrieve rows from a set, in order to make updates or deletions.
cursor iteration
The process of repeatedly moving the cursor to the next element in a collection until some condition is satisfied.
custom logic connection
A connection that causes customized C or C++ code to be run. This connection can be triggered either when an attribute's value changes or an event occurs. See attribute, connection, event.
 
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