T
 
table
(1) An array of data, each item of which can be unambiguously identified by means of one or more arguments. I. A. (2) In SQL, a named data object consisting of a specific number of columns and some unordered rows. IBM. See Structured Query Language.
table type
A category of database table, such as user table, system catalog table, or view.
tabular implementation
An implementation that stores the location of elements in tables. Elements in a tabular implementation are accessed by using indices to arrays.
tabular sequence
A sequence that uses a tabular implementation.
task
(1) In a multiprogramming or multiprocessing environment, one or more sequences of instructions treated by a control program as an element of work to be accomplished by a computer. I, ANSI. (2) A routine that is used to simulate the operation of programs. Tasks are said to be nonpreemptive when only a single task is executing at any one time.
taskbar
A bar on the graphic user interface that shows all open applications and active windows. Clicking any task button on the taskbar brings the corresponding session to the foreground.
task library
A class library that provides the facilities to write programs that are made up of tasks.
template
A family of classes or functions where the code remains invariant but operates with variable types.
template class
A class instance generated by a class template.
template function
A function generated by a function template. The code of a template function remains invariant but operates with a variety of data types.
terminal
See leaf.
text file
A file that contains characters organized into one or more lines. The lines must not contain null characters and none can exceed the maximum line length allowed by the implementation. A text file can include control or other nonprintable characters (other than the null character).
this
A C++ keyword that identifies a special type of pointer in a member function, one that references the class object with which the member function was invoked.
this collection
The collection to which a function is applied.
thread
(1) The smallest unit or path of execution within a process. IBM. (2) A piece of executing code. In Windows, each thread is allocated its own stack from the owning process's 4-GB address space, and each one has its own set of processor registers, called the thread's context. See also primary thread, zero page thread.
thread-local storage
A mechanism in the Windows operating system that allows each thread in a multithread process to allocate storage for its corresponding data.
thread synchronization
The ability to synchronize the activities of various threads. A thread synchronizes itself with another thread by putting itself to sleep. Before doing so, the thread notifies the operating system as to what event has to occur in order for the thread to resume execution.
throw expression
(C++ only) The keyword 'throw,' optionally followed by an operand. This operand determines the value of the exception object to be thrown. If no such operand is present, the exception currently being handled is rethrown.
tilde
The character ~. This character is named <tilde> in the portable character set.
time code
See SMPTE time code.
time on the stack
Total time a call is on the call stack while its thread is executing.
token
The smallest independent unit of meaning of a program as defined either by a parser or a lexical analyzer. IBM. In C++, there are five kinds of tokens: identifiers, keywords, literals, operators, and other separators.
token stream
Source code from which all processor directives have been removed and in which all macros have been expanded. The preprocessor converts the source code to a token stream that can be read by the C++ parser. In the VisualAge C++ IDE, access to this code is provided through the token stream view.
toolbar
A toolbar is a window whose buttons represent tools, menu items, or actions. The toolbar can be located along the top, bottom, or sides of a frame window or can "float" and be positioned anywhere on your desktop. You can also have multiple toolbars with a variety of different toolbar buttons using text, bitmaps, or both.
transient data
Data that does not persist after a routine has finished executing. Transient data may be automatically initialized to a certain value upon entry and reentry to a routine.
translation
The process of transforming all or part of a source program into a program image that contains all the information needed for the program to run.
translation unit
(1) A source file together with all headers and source files included via the preprocessing directive #include, less any source files skipped by any of the conditional inclusion preprocessing directives. ANSI.
transparency
A selected color or area on a graphics screen that allows the video or graphic element behind it to become visible.
transparent color
(1) A clear color used to indicate the part of the bitmap that is not drawn for the bitmap. The area under the bitmap is not overpainted for areas of the bitmap that are set to the transparent color. (2) Video information is considered as being present on the video plane that is maintained behind the graphics plane. When an area on the graphics plane is painted with a transparent color, the video information in the video plane is made visible.
trap
An unprogrammed conditional jump to a specified address that is automatically activated by hardware. A recording is made of the location from which the jump occurred. I.
treble
(1) The upper half of the whole vocal or instrumental tonal range. (2) The higher portion of the audio frequency range in sound recording.
tree
An abstract data structure in the form of a hierarchical collection of nodes that can have an arbitrary number of references to other nodes. There is exactly one path between any two nodes. See root, node.
tree control
A type of control that shows the hierarchical relationships among a set of objects by indenting some of them, as in an outline. The user can expand or collapse the various branches (levels) of the tree (outline).
trigraph
In the C and C++ languages, a sequence of three characters, the first two of which are question marks. Before any other processing takes place, the trigraph is replaced by a corresponding single character. Trigraphs are used to represent characters that are reserved as control characters. See control character, digraph.
true and additional
The most accurate or most descriptive (primary) type of an object (true) and the other or secondary types (additional). For example, if the object is a text file, its true type is text; if the file is a C source code file, its true type is C code.
try block
A block that may invoke a known C++ exception, in which case control is passed to a handler.
type
The description of the data and the operations that can be performed on or by the data.
type balancing
A conversion that makes both operands the same data type. If the operands do not have data types of the same size, the compiler converts the value of the operand with the smaller type to a value having the larger type.
type definition
A definition of a name for a data type. IBM.
typed implementation class
A class that implements a concrete class and provides an interface that is specific to a given element type. This interface allows the compiler to verify that, for example, integers cannot be added to a set of strings. See concrete class.
typeface
A typeface is a unique name, usually registered, which identifies a font by the attributes of the characters in the font. Different parts of a type character such as stroke width, serifs, and vertex shaping, are all used to distinguish one font from another. The size of type is measured in points, and the weight of type refers to the heaviness of the type characters. The most commonly used typefaces are Courier, Helvetica, and Times Roman.
typeless implementation class
A class that implements a concrete class and provides an interface that is not specific to a given element type. See concrete class.
type-safe linkage
A method for ensuring strict typing in C++ by resolving references to functions only when argument types and return values match or have defined conversions, as well as matching function names.
type specifier
In declarations, an indication of the data type of an object or function being declared.
 
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