E-F

elementary data type

Data types that a programming language recognizes and can deal with automatically; in C/C++ these include char , int , float , and pointers to these and pointers to pointers (recursively).

encapsulation

A principle according to which both the data and the operation with it are enclosed within a module and not generally available to other modules.

environment

Usually, a set of environment variables for a process.

environment variable

A set of variables that are set prior to a program's execution and to which the program has access.

exception

An event that occurs during program execution that disrupts the normal flow of instructions.

exception-safe code

Code that preserves certain invariants (usually the use and ownership of resources) after an exception occurs - usually by restoring the state of the process to the one that obtained before the exception.

exception-unsafe code

Code that is not exception-safe.

exec ()

A family of UNIX system calls to execute a program within the process in which it is used.

executable file

A synonym for load module.

executable module

A synonym for load module.

extendibility

A characteristic of software whose functionality may be extended if necessary.

fault-tolerant software

A software system so designed that it continues to work even if fatal errors in execution are encountered .

FIFO

A named pipe; an acronym standing for "first in, first out".

flat-table approach

A program structure resembling cards spread on a flat table, where a function (procedure) is likened to a card; the main implication is that functions cannot be defined within functions.

flow of control

Sequence indicating which of the functions has "control" (i.e., is being executed).

foreign key

An item in a table A of a relational database whose value comes from another table B . Only in table B can the value be modified; in table A , the value is used as a "link" - in essence linking A to B . Foreign keys are used to capture relationships among tables.

fork()

A UNIX system call to create a new process.

fragmentation

During dynamic memory allocation, the process manager may need to carve out a segment to allocate from a bigger one. The left-over segment may be too small to be of any use; this unpleasant aspect of allocation is often called fragmentation.

free()

A standard C/C++ function providing a platform-independent interface to the process memory manager; used to deallocate memory.

free store

A synonym for system heap.

function

A subprogram module in C/C++ with a precisely defined interface; in general the term function refers to a module that returns a value. In C/C++, modules are presumed to return a value (even if they do not), so the term is used for all subprogram modules.

function argument

A synonym for argument (of a function).

function call

A synonym for call (to a function).

function header

A construct in C/C++ syntax that describes the function's interface.