HP-UX Linker and Libraries User's Guide

dynamic loading
library
An SVR4 term for a shared library.
dynamic search
path
The process that allows the location of shared libraries to be specified at runtime.
entry point The location at which a program starts running after HP-UX loads it into memory. The entry point
is defined by the symbol $START$ in crt0.o.
explicit loading The process of using the shl_load(3X) function to load a shared library into a running program.
export stub A short code segment generated by the linker for a global definition in a shared library. External
calls to shared library procedures go through the export stub. See also import stub.
export symbol A symbol definition that may be referenced outside the library.
exporting a
symbol
Making a symbol visible to code outside the module in which the symbol was defined. This is
usually done with the +e or -E option.
external reference A reference to a symbol defined outside an object file.
feedback-directed
positioning
An optimization technique wherein procedures are relocated in a program, based on profiling
data obtained from running the program. Feedback-directed positioning is one of the optimizations
performed during profile-based optimization.
file descriptor A file descriptor is returned by the open(2), creat(2), and dup(2) system calls. The file descriptor
is used by other system calls (for example, read(2), write(2), and close(2)) to refer to a the file.
filters Programs that accept input data and modify it in some way before passing it on. For example,
the pr command is a filter.
flush The process of emptying a buffer's contents and resetting its internal data structures.
global definition A definition of a procedure, function, or data item that can be accessed by code in another object
file.
header string A string, !<arch>\n, which identifies a file as an archive created by ar (\n represents the newline
character).
hiding a symbol Making a symbol invisible to code outside the module in which the symbol was defined.
Accomplished with the -h linker option.
I-SOM Intermediate code-System Object Module. Used during profile-based optimizations and level-4
optimization.
immediate binding By default, the dynamic loader attempts to bind all symbols in a shared library when a program
starts up - known as immediate binding. Compare with deferred binding.
implicit address
dependency
Writing code that relies on the linker to locate a symbol in a particular location or in a particular
order in relation to other symbols.
implicit loading Occurs when the dynamic loader automatically loads any required libraries when a program
starts execution. Compare with explicit loading.
import stub A short code segment generated by the linker for external references to shared library routines.
See also export stub.
import symbol An external reference made from a library.
incomplete
executable
An executable (a.out) file that uses shared libraries. It is incomplete because it does not actually
contain the shared library code that it uses; instead, the shared library code is attached when
the program runs. Compare with complete executable.
indirect addressing The process of accessing a memory location through a memory address that is stored in memory
or a register.
initializer An initialization routine that is called when a shared library is loaded or unloaded.
intermediate code A representation of object code that is at a lower level than the source code, but at a higher level
than the object code.
library A file containing object code for subroutines and data that can be used by programs.
link order The order in which object files and libraries are specified on the linker command line.
link-edit phase The compilation phase in which the compiler calls the linker to create an executable (a.out) file
from object modules and libraries.
226 Glossary