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GNU Info File | 1995-11-26 | 41.8 KB | 896 lines

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 they sued Borland; they won in the trial court (no surprise, since it was the same court that had ruled for Lotus twice before), but the decision was reversed by the court of appeals, with help from the League for Programming Freedom in the form of a friend-of-the-court brief. We are now waiting to see if the Supreme Court will hear the case. If it does, the League for Programming Freedom will again submit a brief. The battle is not over. Just this summer a company that produced a simulator for a CDC computer was shut down by a copyright lawsuit by CDC, which 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.