source: trunk/third/gcc/gcc.info-1 @ 8834

This is Info file gcc.info, produced by Makeinfo-1.55 from the input
file gcc.texi.

   This file documents the use and the internals of the GNU compiler.

   Published by the Free Software Foundation 59 Temple Place - Suite 330
Boston, MA 02111-1307 USA

   Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995 Free Software
Foundation, Inc.

   Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided also
that the sections entitled "GNU General Public License," "Funding for
Free Software," and "Protect Your Freedom--Fight `Look And Feel'" are
included exactly as in the original, and provided that the entire
resulting derived work is distributed under the terms of a permission
notice identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that the sections entitled "GNU General Public
License," "Funding for Free Software," and "Protect Your Freedom--Fight
`Look And Feel'", and this permission notice, may be included in
translations approved by the Free Software Foundation instead of in the
original English.


File: gcc.info,  Node: Top,  Next: Copying,  Up: (DIR)

Introduction
************

   This manual documents how to run, install and port the GNU compiler,
as well as its new features and incompatibilities, and how to report
bugs.  It corresponds to GNU CC version 2.7.2.

* Menu:

* Copying::         GNU General Public License says
                     how you can copy and share GNU CC.
* Contributors::    People who have contributed to GNU CC.
* Funding::         How to help assure funding for free software.
* Look and Feel::   Protect your freedom--fight "look and feel".

* G++ and GCC::     You can compile C or C++ programs.
* Invoking GCC::    Command options supported by `gcc'.
* Installation::    How to configure, compile and install GNU CC.
* C Extensions::    GNU extensions to the C language family.
* C++ Extensions::  GNU extensions to the C++ language.
* Trouble::         If you have trouble installing GNU CC.
* Bugs::            How, why and where to report bugs.
* Service::         How to find suppliers of support for GNU CC.
* VMS::             Using GNU CC on VMS.

* Portability::     Goals of GNU CC's portability features.
* Interface::       Function-call interface of GNU CC output.
* Passes::          Order of passes, what they do, and what each file is for.
* RTL::             The intermediate representation that most passes work on.
* Machine Desc::    How to write machine description instruction patterns.
* Target Macros::   How to write the machine description C macros.
* Config::          Writing the `xm-MACHINE.h' file.
* Fragments::       Writing the `t-TARGET' and `x-HOST' files.

* Index::           Index of concepts and symbol names.


File: gcc.info,  Node: Copying,  Next: Contributors,  Prev: Top,  Up: Top

GNU GENERAL PUBLIC LICENSE
**************************

                         Version 2, June 1991

     Copyright (C) 1989, 1991 Free Software Foundation, Inc.
     59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
     
     Everyone is permitted to copy and distribute verbatim copies
     of this license document, but changing it is not allowed.

Preamble
========

   The licenses for most software are designed to take away your
freedom to share and change it.  By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change free
software--to make sure the software is free for all its users.  This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it.  (Some other Free Software Foundation software is covered by
the GNU Library General Public License instead.)  You can apply it to
your programs, too.

   When we speak of free software, we are referring to freedom, not
price.  Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
this service if you wish), that you receive source code or can get it
if you want it, that you can change the software or use pieces of it in
new free programs; and that you know you can do these things.

   To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.

   For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have.  You must make sure that they, too, receive or can get the
source code.  And you must show them these terms so they know their
rights.

   We protect your rights with two steps: (1) copyright the software,
and (2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.

   Also, for each author's protection and ours, we want to make certain
that everyone understands that there is no warranty for this free
software.  If the software is modified by someone else and passed on, we
want its recipients to know that what they have is not the original, so
that any problems introduced by others will not reflect on the original
authors' reputations.

   Finally, any free program is threatened constantly by software
patents.  We wish to avoid the danger that redistributors of a free
program will individually obtain patent licenses, in effect making the
program proprietary.  To prevent this, we have made it clear that any
patent must be licensed for everyone's free use or not licensed at all.

   The precise terms and conditions for copying, distribution and
modification follow.

    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:

       a. You must cause the modified files to carry prominent notices
          stating that you changed the files and the date of any change.

       b. 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.

       c. 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:

       a. 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,

       b. 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,

       c. 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.

     ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES.
     Copyright (C) 19YY  NAME OF AUTHOR
     
     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 OF TY COON, 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.


File: gcc.info,  Node: Contributors,  Next: Funding,  Prev: Copying,  Up: Top

Contributors to GNU CC
**********************

   In addition to Richard Stallman, several people have written parts
of GNU CC.

   * The idea of using RTL and some of the optimization ideas came from
     the program PO written at the University of Arizona by Jack
     Davidson and Christopher Fraser.  See "Register Allocation and
     Exhaustive Peephole Optimization", Software Practice and
     Experience 14 (9), Sept. 1984, 857-866.

   * Paul Rubin wrote most of the preprocessor.

   * Leonard Tower wrote parts of the parser, RTL generator, and RTL
     definitions, and of the Vax machine description.

   * Ted Lemon wrote parts of the RTL reader and printer.

   * Jim Wilson implemented loop strength reduction and some other loop
     optimizations.

   * Nobuyuki Hikichi of Software Research Associates, Tokyo,
     contributed the support for the Sony NEWS machine.

   * Charles LaBrec contributed the support for the Integrated Solutions
     68020 system.

   * Michael Tiemann of Cygnus Support wrote the front end for C++, as
     well as the support for inline functions and instruction
     scheduling.  Also the descriptions of the National Semiconductor
     32000 series cpu, the SPARC cpu and part of the Motorola 88000 cpu.

   * Gerald Baumgartner added the signature extension to the C++
     front-end.

   * Jan Stein of the Chalmers Computer Society provided support for
     Genix, as well as part of the 32000 machine description.

   * Randy Smith finished the Sun FPA support.

   * Robert Brown implemented the support for Encore 32000 systems.

   * David Kashtan of SRI adapted GNU CC to VMS.

   * Alex Crain provided changes for the 3b1.

   * Greg Satz and Chris Hanson assisted in making GNU CC work on HP-UX
     for the 9000 series 300.

   * William Schelter did most of the work on the Intel 80386 support.

   * Christopher Smith did the port for Convex machines.

   * Paul Petersen wrote the machine description for the Alliant FX/8.

   * Dario Dariol contributed the four varieties of sample programs
     that print a copy of their source.

   * Alain Lichnewsky ported GNU CC to the Mips cpu.

   * Devon Bowen, Dale Wiles and Kevin Zachmann ported GNU CC to the
     Tahoe.

   * Jonathan Stone wrote the machine description for the Pyramid
     computer.

   * Gary Miller ported GNU CC to Charles River Data Systems machines.

   * Richard Kenner of the New York University Ultracomputer Research
     Laboratory wrote the machine descriptions for the AMD 29000, the
     DEC Alpha, the IBM RT PC, and the IBM RS/6000 as well as the
     support for instruction attributes.  He also made changes to
     better support RISC processors including changes to common
     subexpression elimination, strength reduction, function calling
     sequence handling, and condition code support, in addition to
     generalizing the code for frame pointer elimination.

   * Richard Kenner and Michael Tiemann jointly developed reorg.c, the
     delay slot scheduler.

   * Mike Meissner and Tom Wood of Data General finished the port to the
     Motorola 88000.

   * Masanobu Yuhara of Fujitsu Laboratories implemented the machine
     description for the Tron architecture (specifically, the Gmicro).

   * NeXT, Inc. donated the front end that supports the Objective C
     language.

   * James van Artsdalen wrote the code that makes efficient use of the
     Intel 80387 register stack.

   * Mike Meissner at the Open Software Foundation finished the port to
     the MIPS cpu, including adding ECOFF debug support, and worked on
     the Intel port for the Intel 80386 cpu.

   * Ron Guilmette implemented the `protoize' and `unprotoize' tools,
     the support for Dwarf symbolic debugging information, and much of
     the support for System V Release 4.  He has also worked heavily on
     the Intel 386 and 860 support.

   * Torbjorn Granlund implemented multiply- and divide-by-constant
     optimization, improved long long support, and improved leaf
     function register allocation.

   * Mike Stump implemented the support for Elxsi 64 bit CPU.

   * John Wehle added the machine description for the Western Electric
     32000 processor used in several 3b series machines (no relation to
     the National Semiconductor 32000 processor).

   * Holger Teutsch provided the support for the Clipper cpu.

   * Kresten Krab Thorup wrote the run time support for the Objective C
     language.

   * Stephen Moshier contributed the floating point emulator that
     assists in cross-compilation and permits support for floating
     point numbers wider than 64 bits.

   * David Edelsohn contributed the changes to RS/6000 port to make it
     support the PowerPC and POWER2 architectures.

   * Steve Chamberlain wrote the support for the Hitachi SH processor.

   * Peter Schauer wrote the code to allow debugging to work on the
     Alpha.

   * Oliver M. Kellogg of Deutsche Aerospace contributed the port to the
     MIL-STD-1750A.

   * Michael K. Gschwind contributed the port to the PDP-11.


File: gcc.info,  Node: Funding,  Next: Look and Feel,  Prev: Contributors,  Up: Top

Funding Free Software
*********************

   If you want to have more free software a few years from now, it makes
sense for you to help encourage people to contribute funds for its
development.  The most effective approach known is to encourage
commercial redistributors to donate.

   Users of free software systems can boost the pace of development by
encouraging for-a-fee distributors to donate part of their selling price
to free software developers--the Free Software Foundation, and others.

   The way to convince distributors to do this is to demand it and
expect it from them.  So when you compare distributors, judge them
partly by how much they give to free software development.  Show
distributors they must compete to be the one who gives the most.

   To make this approach work, you must insist on numbers that you can
compare, such as, "We will donate ten dollars to the Frobnitz project
for each disk sold."  Don't be satisfied with a vague promise, such as
"A portion of the profits are donated," since it doesn't give a basis
for comparison.

   Even a precise fraction "of the profits from this disk" is not very
meaningful, since creative accounting and unrelated business decisions
can greatly alter what fraction of the sales price counts as profit.
If the price you pay is $50, ten percent of the profit is probably less
than a dollar; it might be a few cents, or nothing at all.

   Some redistributors do development work themselves.  This is useful
too; but to keep everyone honest, you need to inquire how much they do,
and what kind.  Some kinds of development make much more long-term
difference than others.  For example, maintaining a separate version of
a program contributes very little; maintaining the standard version of a
program for the whole community contributes much.  Easy new ports
contribute little, since someone else would surely do them; difficult
ports such as adding a new CPU to the GNU C compiler contribute more;
major new features or packages contribute the most.

   By establishing the idea that supporting further development is "the
proper thing to do" when distributing free software for a fee, we can
assure a steady flow of resources into making more free software.

     Copyright (C) 1994 Free Software Foundation, Inc.
     Verbatim copying and redistribution of this section is permitted
     without royalty; alteration is not permitted.


File: gcc.info,  Node: Look and Feel,  Next: G++ and GCC,  Prev: Funding,  Up: Top

Protect Your Freedom--Fight "Look And Feel"
*******************************************

     This section is a political message from the League for Programming
     Freedom to the users of GNU CC.  We have included it here because
     the issue of interface copyright is important to the GNU project.

   Apple, Lotus, and now CDC have tried to create a new form of legal
monopoly: a copyright on a user interface.

   An interface is a kind of language--a set of conventions for
communication between two entities, human or machine.  Until a few years
ago, the law seemed clear: interfaces were outside the domain of
copyright, so programmers could program freely and implement whatever
interface the users demanded.  Imitating de-facto standard interfaces,
sometimes with improvements, was standard practice in the computer
field.  These improvements, if accepted by the users, caught on and
became the norm; in this way, much progress took place.

   Computer users, and most software developers, were happy with this
state of affairs.  However, large companies such as Apple and Lotus
would prefer a different system--one in which they can own interfaces
and thereby rid themselves of all serious competitors.  They hope that
interface copyright will give them, in effect, monopolies on major
classes of software.

   Other large companies such as IBM and Digital also favor interface
monopolies, for the same reason: if languages become property, they
expect to own many de-facto standard languages.  But Apple and Lotus are
the ones who have actually sued.  Apple's lawsuit was defeated, for
reasons only partly related to the general issue of interface copyright.

   Lotus won lawsuits against two small companies, which were thus put
out of business.  Then Lotus sued Borland; Lotus won in the trial court
(no surprise, since it was the same court that had ruled for Lotus twice
before), but the court of appeals ruled in favor of Borland, which was
assisted by a friend-of-the-court brief from the League for Programming
Freedom.

   Lotus appealed the case to the Supreme Court, which heard the case
but was unable to reach a decision.  This failure means that the appeals
court decision stands, in one portion of the United States, and may
influence the other appeals courts, but it does not set a nationwide
precedent.  The battle is not over, and it is not limited to the United
States.

   The battle is extending into other areas of software as well.  In
1995 a company that produced a simulator for a CDC computer was shut
down by a copyright lawsuit, in which CDC charged that the simulator
infringed the copyright on the manuals for the computer.

   If the monopolists get their way, they will hobble the software
field:

   * Gratuitous incompatibilities will burden users.  Imagine if each
     car manufacturer had to design a different way to start, stop, and
     steer a car.

   * Users will be "locked in" to whichever interface they learn; then
     they will be prisoners of one supplier, who will charge a
     monopolistic price.

   * Large companies have an unfair advantage wherever lawsuits become
     commonplace.  Since they can afford to sue, they can intimidate
     smaller developers with threats even when they don't really have a
     case.

   * Interface improvements will come slower, since incremental
     evolution through creative partial imitation will no longer occur.

   If interface monopolies are accepted, other large companies are
waiting to grab theirs:

   * Adobe is expected to claim a monopoly on the interfaces of various
     popular application programs, if Lotus ultimately wins the case
     against Borland.

   * Open Computing magazine reported a Microsoft vice president as
     threatening to sue people who imitate the interface of Windows.

   Users invest a great deal of time and money in learning to use
computer interfaces.  Far more, in fact, than software developers
invest in developing *and even implementing* the interfaces.  Whoever
can own an interface, has made its users into captives, and
misappropriated their investment.

   To protect our freedom from monopolies like these, a group of
programmers and users have formed a grass-roots political organization,
the League for Programming Freedom.

   The purpose of the League is to oppose monopolistic practices such as
interface copyright and software patents.  The League calls for a return
to the legal policies of the recent past, in which programmers could
program freely.  The League is not concerned with free software as an
issue, and is not affiliated with the Free Software Foundation.

   The League's activities include publicizing the issues, as is being
done here, and filing friend-of-the-court briefs on behalf of
defendants sued by monopolists.

   The League's membership rolls include Donald Knuth, the foremost
authority on algorithms, John McCarthy, inventor of Lisp, Marvin Minsky,
founder of the MIT Artificial Intelligence lab, Guy L.  Steele, Jr.,
author of well-known books on Lisp and C, as well as Richard Stallman,
the developer of GNU CC.  Please join and add your name to the list.
Membership dues in the League are $42 per year for programmers, managers
and professionals; $10.50 for students; $21 for others.

   Activist members are especially important, but members who have no
time to give are also important.  Surveys at major ACM conferences have
indicated a vast majority of attendees agree with the League on both
issues (interface copyrights and software patents).  If just ten percent
of the programmers who agree with the League join the League, we will
probably triumph.

   To join, or for more information, phone (617) 243-4091 or write to:

     League for Programming Freedom
     1 Kendall Square #143
     P.O. Box 9171
     Cambridge, MA 02139

   You can also send electronic mail to `lpf@uunet.uu.net'.

   In addition to joining the League, here are some suggestions from the
League for other things you can do to protect your freedom to write
programs:

   * Tell your friends and colleagues about this issue and how it
     threatens to ruin the computer industry.

   * Mention that you are a League member in your `.signature', and
     mention the League's email address for inquiries.

   * Ask the companies you consider working for or working with to make
     statements against software monopolies, and give preference to
     those that do.

   * When employers ask you to sign contracts giving them copyright on
     your work, insist on a clause saying they will not claim the
     copyright covers imitating the interface.

   * When employers ask you to sign contracts giving them patent rights,
     insist on clauses saying they can use these rights only
     defensively.  Don't rely on "company policy," since that can
     change at any time; don't rely on an individual executive's
     private word, since that person may be replaced.  Get a commitment
     just as binding as the commitment they get from you.

   * Write to Congress to explain the importance of these issues.

          House Subcommittee on Intellectual Property
          2137 Rayburn Bldg
          Washington, DC 20515
          
          Senate Subcommittee on Patents, Trademarks and Copyrights
          United States Senate
          Washington, DC 20510

     (These committees have received lots of mail already; let's give
     them even more.)

   Democracy means nothing if you don't use it.  Stand up and be
counted!


File: gcc.info,  Node: G++ and GCC,  Next: Invoking GCC,  Prev: Look and Feel,  Up: Top

Compile C, C++, or Objective C
******************************

   The C, C++, and Objective C versions of the compiler are integrated;
the GNU C compiler can compile programs written in C, C++, or Objective
C.

   "GCC" is a common shorthand term for the GNU C compiler.  This is
both the most general name for the compiler, and the name used when the
emphasis is on compiling C programs.

   When referring to C++ compilation, it is usual to call the compiler
"G++".  Since there is only one compiler, it is also accurate to call
it "GCC" no matter what the language context; however, the term "G++"
is more useful when the emphasis is on compiling C++ programs.

   We use the name "GNU CC" to refer to the compilation system as a
whole, and more specifically to the language-independent part of the
compiler.  For example, we refer to the optimization options as
affecting the behavior of "GNU CC" or sometimes just "the compiler".

   Front ends for other languages, such as Ada 9X, Fortran, Modula-3,
and Pascal, are under development.  These front-ends, like that for
C++, are built in subdirectories of GNU CC and link to it.  The result
is an integrated compiler that can compile programs written in C, C++,
Objective C, or any of the languages for which you have installed front
ends.

   In this manual, we only discuss the options for the C, Objective-C,
and C++ compilers and those of the GNU CC core.  Consult the
documentation of the other front ends for the options to use when
compiling programs written in other languages.

   G++ is a *compiler*, not merely a preprocessor.  G++ builds object
code directly from your C++ program source.  There is no intermediate C
version of the program.  (By contrast, for example, some other
implementations use a program that generates a C program from your C++
source.)  Avoiding an intermediate C representation of the program means
that you get better object code, and better debugging information.  The
GNU debugger, GDB, works with this information in the object code to
give you comprehensive C++ source-level editing capabilities (*note C
and C++: (gdb.info)C.).


File: gcc.info,  Node: Invoking GCC,  Next: Installation,  Prev: G++ and GCC,  Up: Top

GNU CC Command Options
**********************

   When you invoke GNU CC, it normally does preprocessing, compilation,
assembly and linking.  The "overall options" allow you to stop this
process at an intermediate stage.  For example, the `-c' option says
not to run the linker.  Then the output consists of object files output
by the assembler.

   Other options are passed on to one stage of processing.  Some options
control the preprocessor and others the compiler itself.  Yet other
options control the assembler and linker; most of these are not
documented here, since you rarely need to use any of them.

   Most of the command line options that you can use with GNU CC are
useful for C programs; when an option is only useful with another
language (usually C++), the explanation says so explicitly.  If the
description for a particular option does not mention a source language,
you can use that option with all supported languages.

   *Note Compiling C++ Programs: Invoking G++, for a summary of special
options for compiling C++ programs.

   The `gcc' program accepts options and file names as operands.  Many
options have multiletter names; therefore multiple single-letter options
may *not* be grouped: `-dr' is very different from `-d -r'.

   You can mix options and other arguments.  For the most part, the
order you use doesn't matter.  Order does matter when you use several
options of the same kind; for example, if you specify `-L' more than
once, the directories are searched in the order specified.

   Many options have long names starting with `-f' or with `-W'--for
example, `-fforce-mem', `-fstrength-reduce', `-Wformat' and so on.
Most of these have both positive and negative forms; the negative form
of `-ffoo' would be `-fno-foo'.  This manual documents only one of
these two forms, whichever one is not the default.

* Menu:

* Option Summary::      Brief list of all options, without explanations.
* Overall Options::     Controlling the kind of output:
                        an executable, object files, assembler files,
                        or preprocessed source.
* Invoking G++::        Compiling C++ programs.
* C Dialect Options::   Controlling the variant of C language compiled.
* C++ Dialect Options:: Variations on C++.
* Warning Options::     How picky should the compiler be?
* Debugging Options::   Symbol tables, measurements, and debugging dumps.
* Optimize Options::    How much optimization?
* Preprocessor Options:: Controlling header files and macro definitions.
                         Also, getting dependency information for Make.
* Assembler Options::   Passing options to the assembler.
* Link Options::        Specifying libraries and so on.
* Directory Options::   Where to find header files and libraries.
                        Where to find the compiler executable files.
* Target Options::      Running a cross-compiler, or an old version of GNU CC.
* Submodel Options::    Specifying minor hardware or convention variations,
                        such as 68010 vs 68020.
* Code Gen Options::    Specifying conventions for function calls, data layout
                        and register usage.
* Environment Variables:: Env vars that affect GNU CC.
* Running Protoize::    Automatically adding or removing function prototypes.