C/C++ Programmer's Guide (G06.25+)

Glossary
HP C/C++ Programmer’s Guide for NonStop Systems—429301-008
Glossary-13
translation phases
translation phases. The logical steps that compose the process C uses to translate a
source file into an object file.
translation unit. A source file and all of the header files and source files it includes (using
#include), except for any source lines skipped as the result of conditional
preprocessing directives.
trap. A software interrupt that provides a way of handling certain events, such as detection
of a hardware (or software) fault, a timer expiration, or a lack of system resources. A
trap is often an indication of a run-time event that requires immediate attention; most
such events preclude continuing the interrupted instruction stream. Traps are
generated for TNS Guardian processes. (TNS/R native Guardian processes and all
OSS processes receive signals instead.) An Instruction Failure trap indicates that an
instruction could not execute because the instruction or its data were invalid. Compare
with signal.
type. The intended meaning or interpretation of a value stored in an object or returned by a
function.
user data segment. An automatically allocated segment that provides modifiable, private
storage for the variables of your process.
user library. (1) An object code file that the operating system links to a program file at run
time. A program can have only one user library. See also TNS user library, TNS/R
native user library, and TNS/E native user library.
(2) A library loadfile associated with a program so that it emulates the user library
feature of the operating system on TNS systems. For position-independent code
programs on TNS/R and TNS/E systems, the user library is a dynamic-link library. It is
treated as if it were the first library in the program's libList; thus it is searched first for
symbols required by the program. However, a user library does not appear in the
program's libList; instead, its name is recorded internally in the program's loadfile. A
program can be associated with at most one user library; the association can be
specified using the linker at link time or in a later change command, or at run time
using the process creation interfaces. (The /LIB …/ option to the RUN command in
TACL uses these interfaces.)
word. An instruction-set-defined unit of memory that corresponds to the width of registers
and to the most common and efficient size of memory operations. A TNS word is
2 bytes (16 bits) wide, beginning on any 2-byte boundary in memory. A MIPS RISC
word is 4 bytes (32 bits) wide, beginning on any 4-byte boundary in memory. An
Itanium word is also 4 bytes (32 bits) wide, beginning on any 4-byte boundary in
memory.
working directory. A directory, associated with a process, that is used in pathname
resolution for pathnames that do not begin with a slash (/) character.