C

.C:The extension for a C source file.

call gate:A special descriptor-table entry that describes a subroutine entry point rather than a memory segment. A far call to a call gate selector transfers to the entry point specified in the call gate. This is a feature of the 80286–80486 hardware and is typically used to provide a transition from a lower privilege state to a higher one.

case sensitivity:The distinction made between uppercase and lowercase letters. For example, “MyFile” and “MYFILE” are considered to be different strings in a case-sensitive situation but are understood to be the same string if case is not sensitive.

CGA (color graphics adapter):A video adapter capable of displaying text characters or graphics pixels in low resolution in up to 16 colors.

character string:A sequence of bytes treated as a set of ASCII letters, numbers, and other symbols. A character string is often enclosed in single quotation marks (' ') or double quotation marks (" ").

child process:A process created by another process (its parent process).

click:To press and release quickly one of the mouse buttons (usually the left button) while pointing the mouse pointer to an object on the screen.

clipboard:A temporary storage area for text. The clipboard is used for cut, copy, and paste operations.

.COB:The extension for a COBOL source file.

code symbol:The address of a routine.

.COM:The extension for a DOS executable file that contains a single segment. Tiny-model programs have a .COM extension. See also “tiny memory model.”

command:An instruction you use to control a computer program, such as an operating system or application.

command file:A file containing operating-system commands that can be run from the command line. If the file's extension is .BAT, the command file contains DOS commands. Also called a batch file.

command file (in NMAKE):A text file containing input expected by utilities such as NMAKE.

compact memory model:A program with one code segment and multiple data segments.

compile:To translate programming language statements into a form that can be executed by the computer.

conditional breakpoint:A breakpoint that is taken when a specified expression becomes nonzero (true). A conditional breakpoint is evaluated after every instruction is executed unless an address is also specified. Formerly called tracepoint and watchpoint.

constant:A value that does not change during program execution.

constant expression:Any expression that evaluates to a constant. It may include integer constants, character constants, floating-point constants, enumeration constants, type casts to integral and floating-point types, and other constant expressions. It cannot include a variable or function call.

conventional memory:The first 640K (or sometimes 1MB) of memory under MS-DOS. Also called low memory.

coprocessor:See “8087 family of math processors.”

.CPP:The extension for a C++ source file.

CPU (central processing unit):The main processor in a computer. For example, the CPU that receives and carries out instructions in the PC/AT is an 80286 processor. See also “8086 family of processors.”

CS:IP:The address of the current program location. This is the address of the next instruction to be executed. CS is the value of the Code Segment register, and IP is the value of the Instruction Pointer register.

cursor:The thin blinking line or other character that represents the location of typed input or mouse activity.

.CXX:The extension for a C++ source file.