Parallel Programming Guide for HP-UX Systems

Glossary
ttv
Glossary 209
shared library A library of routines that
can be linked to an executable program at
runtime and shared by several programs
simultaneously. The names of shared
libraries have the .sl extension. See also
archive library..
side effects A condition that prevents the
optimizer from parallelizing a loop. A
procedure that is called within a loop has
side effects if it communicates with the
outside world other than through a return
value.
signal See trap.
stack overflow An error condition that
occurs when the runtime system attempts to
allocate more memory from the stack than is
available. This condition can occur when
attempting to allocate very large arrays or
when a recursive program is out of control.
static variable Variables that are allocated
from static storage (sometimes referred to as
the heap). Static variables have two
characteristics of note:
• They preserve their value for the lifetime
of the program.
• They are initialized when they are
allocated.
By default, program variables in
HP Fortran 90 are automatic.
stream I/O A type of I/O that is based on
the concept of a stream—a flow of data to or
from a file or I/O device. Streams are
managed by the HP-UX operating system.
Access to a stream is provided by a stream
pointer, which is the address of a C-like
structure that contains information about a
stream. When the Fortran 90 intrinsic
FSTREAM is given a logical unit number, it
returns a stream pointer, providing Fortran
programs with access to stream-based
system routines.
symbol table A table of names of
procedures and data, including their offset
addresses. The compiler inserts a symbol
table in the object file for use by the
debugger and profiler.
T- Z
thread An independent flow of control
within a single process, having its own
register set and program counter. The
HP-UX operating system supports
multiple-executing threads within the same
process.
Thread Trace Visualizer See ttv.
trap A change in system state that is caused
by an exception and that may be detected
by the executing program that took the
exception. Traps are hardware features that
may be enabled or disabled. If traps are
enabled, they can change the flow of control
in the program that took the exception. In
response to a trap, the system may generate
a signal (for example, SIGFPE), which the
program can detect. Such a program can be
designed to handle traps. HP Fortran 90
provides the ON statement to handle traps.
ttv A tool for analyzing parallel-executing
programs.