C
c89
A command that invokes the C compiler and whose use is recommended for
portability among systems that conform to the X/Open UNIX CAE specification for
commands and utilities.
See also cc, compiler
call
In a programming language, a statement that invokes a subroutine, function, or
procedure.
call by reference
In a programming language, a method of passing an argument to a subroutine, a
function, or a procedure by supplying the address of the data rather than its
actual value.
See also call by value
call by value
In a programming language, a method of passing an argument to a subroutine, a
function, or a procedure by supplying the actual value of the data.
See also call by reference
CAM (Common Access Method)
The ANSI standard that defines the software interface between device drivers and
the Host Bus Adapters, as well as other means by which SCSI peripherals are
attached to a host processor.
See also SCSI (Small Computer System Interface)
CAM Control Block
See CCB (CAM Control Block)
carriage return
A character that forces all following text to the left margin of the next line or that
signals the end of user input. The Return key is usually used to produce a carriage
return.
case insensitive
Unable to distinguish between uppercase and lowercase letters. A caseinsensitive device or program considers A and a to be the same character.
See also case sensitive
case sensitive
Able to distinguish between uppercase and lowercase letters. A case sensitive
device or program considers A and a to be different characters. Devices and
programs that are part of the DIGITAL UNIX operating system are case sensitive.
See also case insensitive
case statement
In a programming language, a control structure that can take any of several
possible paths depending on the evaluation of its argument.
cbreak mode
A terminal driver operation mode that allows processes to read input as it is
being typed. This mode eliminates the character, mode, and line editing input
facilities.
cc
A command commonly used to invoke the C compiler on UNIX systems.
See also c89, compiler
CCB (CAM Control Block)
The data structure provided by SCSI peripheral drivers to the XPT transport level
to control the execution of a function by the SCSI Interface Module (SIM).
CDB (Command Description Block)
A data structure that contains the SCSI operation code, parameters, and control
bits for a specific operation.
CDE (Common Desktop Environment)
A graphical user interface for interacting with the DIGITAL UNIX operating
system. The CDE interface was jointly developed and is based on industry
standards, including the X Consortium's X Window System and the Open Software
Foundation's Motif interface.
character device
A data storage or transfer device that manipulates data in increments of a single
character; for example, a terminal.
See also block device
character device switch table
The method used by the DIGITAL UNIX operating system to select the entry
points associated with a particular character device.
See also block device switch table
character special file
A file through which processes can access either a character-stream oriented I/O
interface or an unstructured (raw) device, such as a communication line or an
unbuffered magnetic tape or disk.
child process
See parent process
client
A computer system that uses resources provided by another computer system,
called a server.
client process
In the client/server model of communication, a process that requests services
from a server process.
clist
A data structure used by a BSD-type of terminal driver to store data coming from,
or going to, terminals.
See also STREAMS
Command Description Block
See CDB (Command Description Block)
command history
See history list
command mode
A state of a system or device in which the user can enter commands.
command substitution
The ability to capture the output of any command as an argument to another
command by placing that command line within grave accents ( ` ` ). The shell first
executes the command or commands enclosed within the grave accents and then
replaces the whole expression, including grave accents, with their output. This
feature is often used in assignment statements.
comment out
To selectively disable interpretation of a portion of a program or document
source file.
Common Access Method
See CAM (Common Access Method)
Common Desktop Environment
See CDE (Common Desktop Environment)
common internet address notation
On internet networks, the decimal for the 32-bit internet address. Also called
dotted-decimal notation.
communication domain
An abstraction used by the interprocess communication facility of a system to
define the properties of a network. Properties include a set of communication
protocols, rules for manipulating and interpreting names, and the ability to
transmit access rights.
compile
To process one or more program source files in order to produce an executable
binary file or an object file.
compiler
A program that translates programs written in a particular source language into
executable binary files (or into intermediate binary files referred to as object files).
The input can include one or more source-language files together with one or
more object files. Compiled programs execute faster than interpreted programs
because the compiler has already performed the interpretation. The cc program
is a C compiler.
See also binary file, compile, interpreter, object file
compile time
Refers to actions that are taken by a compiler during the compilation of a
program.
See also run time
computer virus
See virus
computer worm
See worm
concatenate
To place together. Data elements such as strings can be concatenated to produce
a string that contains all of the characters of the first original string, followed by
the characters of the next original string, and so on. Files can be concatenated by
combining their contents in a similar manner, either into a new file or into one of
the original files.
conditional compilation
During the compilation of a program, a portion of the process (code block) that is
enabled or disabled by a variable or condition external to the code block under
consideration. For example, a certain program might contain a block that is to be
compiled only if the compilation is performed on a DIGITAL UNIX system.
conditional execution
During the execution of a program, a portion of the program's behavior or output
that is enabled or disabled by a variable or condition. For example, a certain
program might contain code that asks the user questions only if the user initiates
the program to run in a menu mode.
conditional statement
In a programming language, a statement (for example, the if statement) that
evaluates one or more variables or conditions and uses the result to choose one
of several possible paths through the subsequent code.
configuration
1. The machines, devices, and programs that make up a data processing system
or network.
2. The act of making a subsystem, or a set of subsystems, available for use by a
running operating system.
3. The set of configured subsystems in an operating system.
configuration file
A file that specifies the characteristics of a system or subsystem.
connectionless mode
A mode of service supported by a transport endpoint that requires no established
connection for transmitting data. Data is delivered in self-contained units, called
datagrams.
connection-oriented mode
A mode of service supported by a transport endpoint for transmitting data over
an established connection.
construct
A data structure used for a particular purpose.
context search
See global search
control statement
In a programming language, a statement that can cause different actions to
ensue, depending on the results of an evaluation or test.
cooked mode
The condition of a device driver in which the driver interprets the data passing
through it. For example, a UNIX terminal driver operating in cooked mode
translates a Return character from the terminal into a Line Feed character to be
passed to the system.
See also raw mode
cron
A daemon that executes commands at specified times and dates, according to
instructions in the crontab file.
See also daemon
crontab file
A file that specifies the dates and times at which specified commands are to be
executed. The cron daemon examines the crontab file at specified intervals, and
executes the indicated commands at the specified dates and times.
csh
The command that invokes the C shell.
See also C shell, shell
C shell
A command interpreter and interpreted programming language developed at the
University of California at Berkeley; so named because many of its constructs
resemble the equivalent C language constructs.
See also shell
current directory
See working directory
cursor
For video display screens, a symbol that shows the location of keyboard input.
The cursor shows the position at which the next character to be displayed will be
placed.
See also pointer
cursor movement keys
A set of keys, usually labeled with arrows pointing up, down, left, and right, that
position the cursor on a video display screen.
