From The sfront Reference Manual by John Lazzaro and John Wawrzynek.

Part I/6: Change Log and License

Sections

Change Log

The right panel documents the changes made in each sfront release.

Change Log

Version 0.88 -- 12/26/04 (download)

[1] Networking updated to match
draft-ietf-avt-rtp-midi-format-07.

   Chapter M fields for A-BUTTON
   and C-BUTTON use new G bit layout 
   and compute count for large values 
   correctly. 

   Sender supports the oldest-first
   log ordering for Chapters E/A/N.

   Sender supports new Chapter Q 
   coding rule Start and Continue
   commands. 

   SDP sent in SIP INVITEs uses 
   rtp_maxptime and rtp_ptime, and
   uses correct SDP syntax.

[2] The -sip_ip parameter now parses
dotted-quads correctly.

[2] Memory management bugs fixed
(thanks to Graydon Hoare).

[3] Correct value for PI used in
code examples, book (thanks to 
Tiaan Geldenhuys).


Version 0.87 -- 10/15/04

[1] Networking knows the
new IP number of the 
Berkeley SIP server.

[2] Compilation times of
Mac OS X are improved.


Version 0.86 -- 4/24/04 

[1] Networking now conforms
to the RTP payload format for
MIDI under development in the
Audio/Video Transport group
of the Internet Engineering
Task Force.  

[2] The download page no longer
offers RedHat or Debian packages,
because I no longer have root access
to a desktop Linux workstation to
build and test packages.  However,
the official Debian package for
sfront 0.85 still exists, and will 
hopefully be updated to 0.86.

[3] Several minor bugfixes.


Version 0.85 -- 9/13/02

[1] Mac OS X support for
real-time MIDI control, 
using the -cin coremidi
control driver. Up to four
external MIDI sources are
recognized. Virtual sources
are ignored; expect virtual
source support in a future 
release.

[2] Mac OS X memory locking
now works in normal user 
processes, and is no longer 
limited to root.



Version 0.84 -- 8/29/02 

[1] CoreAudio I/O now
works correctly under
Mac OS X 10.2 (Jaguar).
Thanks to Juno.

[2] Large -latency values
no longer hang CoreAudio;
documentation for -latency
option is now accurate for
CoreAudio. Thanks to Manfred
Brockhaus.

[3] Sfront networking now
works under Mac OS X, 
including PPP and DHCP.

Version 0.83 -- 8/11/02 

[1] Low-latency audio
output and input now
supported for Mac OS X
using CoreAudio. 
Developed on a TiBook
under 10.1.5; please
send reports for other
platforms. Thanks to
coreaudio-api and
darwin mailing list
members for extensive
API help.

[2] Compile-time
warnings under 
Visual C++ fixed.
Thanks to Kees van
Prooijen.

Version 0.82 -- 7/23/02

[1] Bugfixes for large
spline and cubicseg
wavetables, and for 
polymorphic opcodes
used in wavetables.
Thanks to Michael B.

[2] SIP server IP 
numbers updated for
sfront networking. To
use earlier sfront 
versions with the
new SIP server, add

-sip_ip 128.32.112.203

to the sfront command
line.


Version 0.81 -- 5/24/02 

[1] Bugfixes for sfront
code generation and for
the SLib library. Thanks
to Manfred Brockhaus and
Michael McGonagle.

Version 0.80 -- 5/08/02 

[1] Sfront complies with
the MPEG 4 Structured 
Audio COR2 Corrigenda
(March 2002). See this
guide to COR2 changes
for more details.

[2] The MP4-SA book is
now licensed under
the GNU Free Documentation
License, and is bundled
with all versions of the
sfront distribution.

[3] Many bugfixes. 


Version 0.79 -- 11/04/01 

[1] Performance tuning for
audio streaming under Mac
OS X. Thanks to Richard 
Dobson and Robert.


Version 0.78 -- 10/23/01 

[1] Sfront buffer overflow
bugfix, caused fatal errors
under Mac OS X. Thanks to
Robert.

Version 0.77 -- 10/12/01 

[1] New mac_carbon
audio driver for Mac OS X,
using the Carbon framework.
Bugfixes for Windows WMME
and DirectSound drivers. 
Thanks to portaudio.com,
Phil Burk, Richard Dobson,
and Dominic Mazzoni.


Version 0.76 -- 9/23/01

[1] Enhanced audio
driver API to support
soundcard APIs that 
require callback functions. 

[2] New ps_win_wmme
and ps_win_ds audio
drivers for Windows
WMME and DirectSound APIs.
Thanks to the PortAudio
team, and testers Richard
Dobson, Peter Maas, Kees van
Prooijen, and Tim Thompson.

[3] Audio drivers now control 
default time option selection.

[4] Many bugfixes in
SAOL audio bus system.
Thanks to Robert Sherry.


Version 0.75 -- 8/13/01 

[0] Sfront networking
now works well with DHCP,
otherwise unchanged from
sfront 0.74. Thanks to
Mike McGonagle.


Version 0.74 -- 8/04/01  

[1] First release for 
sfront networking.

[2] Audio driver for Irix
(6.2 and above). Thanks 
to Michael Pruett (SGI).

[3] The sfront manual is
now under the GFDL, for
Debian compatibility. 
Thanks to Enrique Arnuncio
for help with the Debian
issues. Note the MP4-SA
book license is unchanged.

[4] New SAOL resonant
physical model library.
See examples/bach and
several examples/linux
files for SAOL produced
by the library, and see
sfront/lib/reson/README
for library details.

[5] Many bug fixes,
thanks to Robert Sherry,
Michael McGonagle, and
Kees van Prooijen.

Version 0.72 -- 7/10/01 

[1] The -cin ascii control
driver has been rewritten:
it maps the ASCII keyboard
as a two-octave pentatonic
scale, with fixed note length.
Special keys control MIDI 
presets and channel volume.
Tested under Linux, should 
work on any OS that supports
the termios API.

[2] Sfront now fully tested
under Mac OS X version 10.0.3.
Work on Mac OS 9.1 under MPW
has yet to resolve problems 
related to sample file and
MIDI file reading, and so OS 
X is the most viable option for
sfront Mac OS users. Thanks to
Manfred Brockhaus.

[3] Numerous bug fixes: variable
length core opcodes work in
oparrays, the && and || operators
work for vectors, unused exports 
signal variables work correctly, 
several audio-bus errors fixed, SASL
labelled control statements access
multiple instrs correctly, large 
constant integer values correctly 
supported. Thanks to Robert Sherry
and Axel Nackaerts.


Version 0.71 -- 3/29/01 

[1] Bugfixes for user-defined 
opcodes that use slower-rate 
statements. Thanks to Robert
Sherry and Robin Davies. 


Version 0.70 -- 2/20/01 

[0] Added MPW-related 
bugfix -- otherwise
identical to 0.69, whose
change-log items are 
listed below.

[1] Sfront is compliant
with the COR1 document,
a new MPEG Corrigenda that
updates the SAOL language.
See this appendix of the
MP4-SA Book to learn about 
the SAOL changes in COR1.

[2] New alsaseq control driver
written by Enrique Robledo
Arnuncio, for MIDI control
using the Linux ALSA sequencer.

[3] Many bug fixes, including
compliant global parameter 
krate determination when
srate/krate is non-integral
(thanks to Ross Bencina), 
Macintosh MPW compilation
fixes (thanks to BUYO-BUYO-
IGOR). 


Version 0.68 -- 10/28/00 

[1] C code generated for
MIDI control now compiles
faster.

[2] Many contributed bug
fixes, thanks to Kees van
Prooijen, Richard Dobson,
the saol.net folks, and M. 
Edward Borasky.


Version 0.67 -- 09/09/00 

[0] Another bugfix for
Windows sfront.dsp file
(thanks to Kees van Prooijen).
Rest of items unchanged
since 0.65.

[1] C code generated for
SAOL and SASL wavetables
compiles much quicker and
runs with improved cache
behavior. C code created
for the "sample" wavetable
generator no longer includes
an WAV or AIFF parser,
and moderately-sized constant
tables for all generators are
computed by sfront and placed
into the sa.c file as constant
float arrays. On some machine/
compiler configurations,
the sfront -hexdata flag
offers additional compilation
speedup, by encoding arrays
as hexadecimal strings.

[2] C code generated for 
wide oparrays compiles much
quicker and runs with improved
cache behavior (thanks to 
Richard Dobson). 

[3] Many sa.c memory leaks
involving wavetables have
been fixed, reducing the
working memory space of 
table-intensive programs.

[4] Bugfixes involving the
dur standard name (thanks to
Tobiah), empty opcode 
return() statements (thanks
to Ross Bencina), name
space collisions (thanks to
Aaron Finch), oparrays, and
wavetables.


Version 0.64 -- 08/02/00 

[1] Optimizations for 
accessing global variables
(via import/export) and 
opcode parameters, to 
eliminate unneeded copying.
Programs that use these
language features extensively
should see significiant 
speedups (thanks to Dave
Gillepsie).

[2] Linux rpm and deb binary
packages now available for
download (thanks to Enrique
Arnuncio and Joey Hess).

[3] Bugfixes for fft/ifft
shift-and-add mode (a 
startup artifact was 
eliminated, and an boxcar
windowed fft/ifft pair 
has unity gain, thanks to
Richard Dobson).

[4] Bug fixes for ANSI 
constant compatibility
(thanks for Aaron Finch)
and name-space clashes,
and a null -ain/-aout
driver added was (thanks
to Mike McGonagle).



Version 0.63 -- 07/10/00 

[0] Several cross-platform
bugfixes (Thanks to Michael
McGonagle and Richard Dobson).
Rest of change log from 0.62.

[1] Standard name cpuload
is now supported in -playback
and -timesync mode, for
all drivers. Cpuload is a
ksig, that takes on a value
between 0 (machine is not
loaded at all) and 1 (any
further loading of machine
risks loss of real-time 
playback). Cpuload is 
computed with no temporal
filtering or windowing, 
and shows the performance
on the last kcycle.

[2] The -ain/-aout linux
and -cin linmidi drivers 
are enhanced. The drivers
are more robust against 
lockup and MIDI data loss.
When run as root, the driver
uses POSIX real-time scheduling
to reduce audio dropouts
(while we have carefully
tested these root features,
bugs in programs run as root
can cause file-system damage:
use at your own risk). Sa.c
start-up screen now suggests
the best sfront flags to use
for a given patch. FreeBSD and
linux sources are now merged,
with many of these features
available for both operating
systems. Thanks to Paul 
Barton-Davis, Bertrand Petit,
Benno Senoner, Kai Vehmanen,
and the folks at saol.net.

[3] Bugfixes in: memory
allocation, dsound driver,
random number generators,
polymorphic table opcode
rate semantics, -cin fstr
file streaming, wavetable
generator sizing, and 
array parameters in user
defined opcodes. Thanks
to Richard Dobson and
the folks at saol.net.



Version 0.61 -- 05/28/00 

[1] Sfront is now includes
Slib, a SAOL library that
provides support utilities
to simplify low-level SAOL 
programming. See this new
chapter of the MP4-SA 
book for details.

[2] New linux/linbuzz 
example, that shows the
MIDI features of Slib
in a real-time instrument.

[3] New optimization: faster
execution of expressions like
tableread(t, int(x)), by 
eliminating interpolation code.

[4] Bugfixes for the dynamic
instr command, the outbus command,
the buzz opcode and wavetable
generator, specialop expressions, 
opcode table initializations that
use opcode parameters, send
statements that target the
output_bus, and user-defined
opcode rate warnings.

Version 0.60 -- 05/07/00 

[0] Minor buzz() opcode 
bugfix -- rest of change
log describes changes
between 0.58 and 0.59.

[1] Rate-semantic printf
statement implemented,
and a new book chapter 
on debugging SAOL 
shows how to use it.
Like all sfront SAOL
extensions, sfront 
drops printf statements
as it encodes MP4 files,
and printf is not a reserved
word if the -isosyntax
flag is set. New -isocheck
flag also helps debugging,
adding many run-time checks.

[2] "C pre-processing" of 
SAOL and SASL is now 
integrated into sfront,
with line-number support 
for error messages, a
post-processor that strips
stray semicolons. To support
library development, sfront
now supports multiple global
blocks in a program. Thanks
to Michael McGonagle.

[3] MIDI controller, 
aftertouch, and pitch
bend information is now
visible to effects and
SASL instruments. See
this book section
for details. Thanks to
Robin Davies and saol.net.

[4] Support added to 
querying audio input
sources for sample rate
and channel width of
input_bus, if not
specified in global block.

[5] Control drivers can
now control BIFS variables
(including params[]) as
accessed by SAOL code. 

[6] Bug fixes: expressions
used in array/opcode/table
indexing now executed just
once (formerly done twice
due to buggy rounding code),
buzz opcode now works for
large rolloff and nharm
values, user-defined opcode
calls in the global block
now work correctly, recursive
opcode calls generate an
error message, Kaiser window
table generator bugs fixed.
Many bugs in MIDI File
support fixed (thanks to
saol.net.)



Version 0.58 -- 04/17/00 

[1] The control driver
API has been improved.
It can now support 
compliant execution of
MP4 SA_access_units,
as well as patch editor,
CLI, and symbolic debug
applications. It 
includes many data 
structures that let
the control driver 
discover information
about the SAOL and SASL
files used to generate
the sa.c it lives in.

[2] The programers 
manual for sfront has
been reworked, and now
includes an introductory
section that explains
how to use sfront from
other programs, and a
multi-part manual
on the control driver
interface.

[3] A file streaming
control driver has 
been written to 
demonstrate the new
API. It opens an MP4
file during the start
of sa.c execution, 
seeks past the config
section, and then 
dynamically executes
SA_access_unit stream
packets. It contains
much of the codebase
needed for true
MP4-SA network streamer.

[4] The spline wavetable
generator was described
incorrectly in the MP4-SA
book, and implemented 
incorrectly in sfront.
Both book and program
are now fixed. See this
book section for the
correct syntax (page down
to the spline generator).

[5] SAOL random opcodes
now produce a different
random number stream on
each sa.c run. New
-fixedseed sfront option
simplifies SAOL program
testing, by making all
random opcodes produce a
deterministic number stream
on every sa.c run.
Thanks to Martin Marier and
Michael McGonagle.

[6] Many bugs were 
fixed. Most bugs were
in SASL and SAOL wave
table generator code,
and in the control
driver code. Bugs were
also fixed in the 
linmidi driver.


Version 0.57 -- 03/8/00 


[0] Windows distribution
issues, and several bugs,
that were found in 0.56
are fixed -- thanks to
Daniel Kahlin, Michael
McGonagle, Kees van
Prooijen, and Richard
Dobson. Remaining change
log entries are carried
over from 0.56.

[1] The -bit option now
reads SA files that have
streaming data (i.e.
SA_access_units). All
event_types are supported
(SASL score_lines, MIDI 
midi_events, and the sample
type for table data). SASL
score_lines that use both
relative and absolute
timestamps can be read
(i.e. has_time = 0 and 1).

[2] The -bitout option now
writes binary files that
include SA_access_units. 
The new 

-sstrout filename.sasl 
-mstrout filename.mid

options specify the SASL and
MIDI files for encoding as
SA_access_units. Files 
specified using the older
options:

-sco filename.sasl 
-midi filename.mid

are encoded as part of the
preamble of the binary file
(StructuredAudioSpecificConfig)
as before. If SASL table
commands are used with the
sample wavetable generator,
the WAV or AIFF file specified
becomes a streaming sample
chunk.

[3] Bug fixes: skip and size
fields work correctly in 
sample wavetable generator
(thanks to Bertrand Petit),
bugs in dynamic instrs fixed
(thanks to Michael McGonagle),
bugs in the AIFF audio input
driver fixed.

[4] Default help printout
shortened (-help prints out
the longer option listing).




Version 0.55 -- 02/12/00 

[1] Base frequency and loop
points can be read by the
sample wavetable generator,
for both AIFF and WAV files,
and this looping information
is correctly captured in .mp4
files (Thanks to Kees van
Prooijen).

[2] SAOL template improvements:
the restrictions on the use
of "<" and ">" in maplist
expressions have been removed,
many bugs have been fixed, and
a new template chapter
in the MP4-SA book is now online.

[3] Control and audio drivers
can now access command-line
options of the program containing
them, and policy has been set to
share the command-line-option
namespace. See the
audio driver documentation
and Part III of the control
driver documentation
for details. Thanks to Michael 
McGonagle.

[4] Linux/FreeBSD driver
enhancements: more soundcards
are permitted to use -timesync
mode, and warning messages are
printed for ill-advised use of
timing flags.

[5] Bug fixes: MIDIctrl standard
name now works as an lval, control
driver interface bugs fixed (thanks
to the SAOL Projekt).



Version 0.54 -- 01/27/00 

[1] The sample wavetable 
generator can now read
base frequency and loop
start and end points from
the smpl chunk of Microsoft
WAV files (Thanks to Kees 
van Prooijen). MP4 file encoding
and decoding correctly packs
and unpacks this data into
the binary MP4 encoding.
Bugs handling 8-bit AIFF
and WAV file data in MP4
encoding and decoding and
in sample wavetable generator
fixed.

[2] Concat wavetable generator
bugs fixed.

[3] Several SAOL and SASL file
parsing errors fixed (thanks
to Bertrand Petit and to the
members of the SAOL Projekt).

[4] Non-ANSI strdup() calls
removed from sfront and 
generated code.


Version 0.53 -- 01/12/00 

[1] Several new optimizations: 

   [a] Instr and opcode tables
       generators with constant
       parameters are converted
       to imports tables.

   [b] Instr code in while and
       if-else blocks are now
       rate-optimized (i.e. 
       slower subexpressions 
       are moved to i-rate or
       k-rate if it is safe to
       do so).

[2] Audio drivers for FreeBSD  
(thanks to Bertrand Petit).

[3] New -except sfront option,
includes a signal handler for 
gracefully shutting down audio
drivers if generated C program
terminates abnormally. Compiles
as vanilla ANSI C, but may not
work well on non-POSIX systems
(thanks to Bertrand Petit).

[4] Divide-by-zero bugs 
fixed in the aline, kline,
aexpon, and kexpon core 
opcodes (thanks to Bertrand
Petit). Bugs fixed in table
and tablemap accesses in 
deeply nested oparrays. Bugs
fixed in template expression
substitution.

[5] New binary distributions
for Linux and DOS/Windows.
The DOS/Windows releases
are built using the
dos-gcc cross-compiler that
runs under Linux. 



Version 0.52 -- 01/03/00 

[1] Extensive optimizations
and bug fixes for the 
filter, spectral analysis,
gain control, sample 
conversion, delay, and
effects core opcodes, the
pluck and grain signal
generator core opcodes,
and the spatialize statement.


[2] All a-rate core opcodes
now function correctly when
enclosed in if and while 
statements with a-rate guards
(thanks to Ross Bencina).


[3] Runtimef.c file now 
included in lib/csrc/
directory -- thanks to 
Bertrand Petit.



Version 0.50 -- 12/17/99 

[1] The code sfront 
generates for wavetable
data structures has been
improved, and many core
opcodes and language 
elements run faster as
a result.


[2] Many bug fixes: nested
oparrays of user-defined
opcodes now work correctly,
a specialop bug that broke
the linux/linvoc example is
fixed, and complex wavetable
generates now work correctly.
Thanks to Dan Ellis and 
Reynald Hoskinson.



Version 0.49 -- 12/04/99 

[1] Optimizations of 
several core opcodes:
buzz, aline, kline,
aexpon, and kexpon.


[2] Imports tables are
now implemented as
imports exports tables 
when it is safe to do so.


Version 0.48 -- 11/22/99 

[1] Fixes optimizer bugs, and
adds new optimizations. New 
optimizations focus on effects
instruments, and specializes
generated code to the unique
properties of instruments
launched using send().

[2] Duration and delay 
arguments to SAOL instr
command now correctly 
interpeted as having units
of beats.


Version 0.46 -- 11/16/99 

[1] Fixes optimizer bugs, and
adds new optimizations. New 
optimizations stem from a 
reference-counting scheme that
tracks variables in SAOL code.

[2] Win32 DirectSound output
driver is now works better,
and has been tested on SB
Live, SB16, and Creamware
Pulsar cards. Requires 7.0
version of DirectSound, and
may have problems working 
under NT/Windows 2000. Thanks 
to Vincent Siliakus and Thomas
Jongepier.

[3] New control input driver
alsamidi supports real-time 
MIDI input under Linux using
the ALSA sound system (note
OSS audio input and output
drivers already work with ALSA).
Thanks to Steven Pickles.


Version 0.44 -- 11/01/99 

[1] Fixes optimizer bugs, and
adds minor optimizations. Major
parts of the compiler have been
rewritten to support future 
optimization releases.



Version 0.43 -- 09/28/99 

[1] Fixes code optimization bugs
(0.42 produces incorrect code for 
certain arithmetic expressions).
Running 0.42 with -O0 option 
should avoid these bugs, but
will also avoid all optimization!


Version 0.42 -- 09/19/99 

[1] Rate optimization added
to sfront -- slower-rate
subexpressions are factored
out and executed in a slower
pass. Default is complete 
optimization, new flags
control turning off parts of
the optimizer.

[2] Fixed dsound code generation
bugs (but not underlying sound
generation bugs). Thanks to
Michael Gogins.



Version 0.41 -- 09/10/99 

[1] Fixed bugs affecting the
special "startup" instrument
(thanks to Michel Jullian).

Version 0.40 -- 09/05/99 

[1] Sfront can now handle audio
input and output drivers that 
require floating-point data
buffers. See audio driver
documentation for details.

[2] New -ain and -aout options
for .dat files, the ASCII data
format for the curve graphing
program view (part of the
Chipmunk tools, a UNIX toolset
under the GPL). This option uses
a floating-point driver.

Version 0.39 -- 09/03/99 

[1] Core opcodes now handle 
negative frequency arguments
correctly (except for loscil).
Thanks to Giorgio Zoia (ETH).

[2] Supports Borland C++ compiler
under Windows with very few warning
messages (thanks to Ross Bencina).

Version 0.38 -- 08/31/99 

[1] Supports Borland C++ compiler
under Windows with minimal warning
messages (thanks to Ross Bencina).

Version 0.37 -- 08/27/99 

[1] Many minor changes to support
compliation using Microsoft Visual
C++. 

[2] Bundles all libraries into the
sfront executable, so that the 
binary no longer needs to find the
library directory. 

Version 0.36 -- 08/20/99

[1] Adds linux audio output
and audio and MIDI input
support. 

[2] Core opcode rate semantics
now match saolc.

[3] Removes a printf option that
was not compatible with Microsoft
Visual C, increasing the odds sfront
may compile under Windows w/o UWIN
(thanks to gogins@nyc.pipeline.com).

Version 0.35 -- 07/29/99

Baseline version of sfront, future
entries in this log will describe
changes made to this release.

Sfront License

The Regents of the University of California hold the copyright to sfront.

Sfront is licensed under the GNU license, which is reproduced below.


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Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Preamble

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TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

0. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The "Program", below, refers to any such program or work, and a "work based on the Program" means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term "modification".) Each licensee is addressed as "you".

Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does.

1. You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program.

You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.

2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions:

  1. You must cause the modified files to carry prominent notices stating that you changed the files and the date of any change.
  2. You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.
  3. If the modified program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the most ordinary way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty (or else, saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of this License. (Exception: if the Program itself is interactive but does not normally print such an announcement, your work based on the Program is not required to print an announcement.)

    These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

    Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.

    In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.

    3. You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following:

    1. Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,
    2. Accompany it with a written offer, valid for at least three years, to give any third party, for a charge no more than your cost of physically performing source distribution, a complete machine-readable copy of the corresponding source code, to be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,
    3. Accompany it with the information you received as to the offer to distribute corresponding source code. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form with such an offer, in accord with Subsection b above.)

      The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.

      If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code.

      4. You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.

      5. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program or works based on it.

      6. Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License.

      7. If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program.

      If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply and the section as a whole is intended to apply in other circumstances.

      It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system, which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice.

      This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.

      8. If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License.

      9. The Free Software Foundation may publish revised and/or new versions of the General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.

      Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation.

      10. If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally.

      
      
      NO WARRANTY

      11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

      12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

      
      
      END OF TERMS AND CONDITIONS
      
      
      How to Apply These Terms to Your New Programs

      If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.

      To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found.

       

      Copyright (C) 20yy

      This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

      This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

      You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

      Also add information on how to contact you by electronic and paper mail.

      If the program is interactive, make it output a short notice like this when it starts in an interactive mode:

       

      Gnomovision version 69, Copyright (C) 19yy name of author Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details.

      The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than `show w' and `show c'; they could even be mouse-clicks or menu items--whatever suits your program.

      You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the program, if necessary. Here is a sample; alter the names:

       

      Yoyodyne, Inc., hereby disclaims all copyright interest in the program `Gnomovision' (which makes passes at compilers) written by James Hacker.

      (signature) 1 April 1989
      Ty Coon, President of Vice

      This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Library General Public License instead of this License.

 

Summary

This concludes the users guide. The next section of the manual is for programmers wishing to modify sfront or write audio drivers for sfront

Next section: Part II/1: Adding Drivers to Sfront

 

Copyright 1999 John Lazzaro and John Wawrzynek.