Path: senator-bedfellow.mit.edu!bloom-beacon.mit.edu!usc!elroy.jpl.nasa.gov!ames!agate!usenet From: jbuck@ohm.berkeley.edu (Joe Buck) Newsgroups: gnu.g++.help,comp.lang.c++,news.answers,comp.answers Subject: FAQ for g++ and libg++, plain text version [Revised 15 Aug 1993] Supersedes: Followup-To: poster Date: 15 Aug 1993 13:00:12 GMT Organization: University of California, Berkeley Lines: 777 Approved: news-answers-request@MIT.edu Expires: 15 Sep 1993 00:00:00 GMT Message-ID: NNTP-Posting-Host: ohm.eecs.berkeley.edu Xref: senator-bedfellow.mit.edu gnu.g++.help:3943 comp.lang.c++:50215 news.answers:11394 comp.answers:1606 Archive-name: g++-FAQ/plain Last-modified: 15 Aug 1993 Frequency: bimonthly [ this is the plain text version, the parent is the texinfo version ] Preface ******* This is a list of frequently asked questions (FAQ) for g++ users; thanks to all those who sent suggestions for improvements. Thanks to Marcus Speh for doing the index. Many FAQ's, including this one, are available on the archive site rtfm.mit.edu, in the directory pub/usenet/news.answers. This FAQ may be found in the subdirectory g++-FAQ. There have been many, many changes since the last version of this list, prompted by a major release of gcc. I've fixed this document as best I could, but I'm sure it will need some more work. Please send fixes, and please be kind. I'm looking for new questions (*with* answers), better answers, or both. One thing that's missing is a section on templates and template problems with g++; I'm looking for contributions on this score. You can mail comments, suggestions, flames, etc. to jbuck@ohm.berkeley.edu. Please don't assume, though, that because my name is on this thing that I am the world expert on g++/C++ and you should mail all your tricky questions to me. I'd like to be helpful but I'm getting more of this than I can deal with lately. This FAQ is intended to supplement, not replace, Marshall Cline's excellent FAQ for the C++ language and for the newsgroup comp.lang.c++. Especially if g++ is the first C++ compiler you've ever used, the question "How do I do with g++?" is probably really "How do I do in C++?". You can obtain the C++ FAQ by anonymous FTP from sun.soe.clarkson.edu [128.153.12.3], in the file ~ftp/pub/C++/FAQ. (There is also a mail server for that FAQ, but it seems to be broken). Obtaining Source Code ********************* How do I get a copy of g++ for Unix? ==================================== First, you may already have it if you have gcc for your platform; g++ and gcc are combined now (as of gcc version 2.0). You can get g++ from a friend who has a copy, by anonymous FTP or UUCP, or by ordering a tape or CD-ROM from the Free Software Foundation. The Free Software Foundation is a nonprofit organization that distributes software and manuals to raise funds for more GNU development. Getting your copy from the FSF contributes directly to paying staff to develop GNU software. CD-ROMs cost $400 if an organization is buying, or $100 if an individual is buying. Tapes cost around $200 depending on media type. I recommend asking for version 2, not version 1, of g++. For more information about ordering from the FSF, contact gnu@prep.ai.mit.edu, phone (617) 876-3296 or anonymous ftp file /pub/gnu/GNUinfo/ORDERS from prep.ai.mit.edu or one of the sites listed below. Here is a list of anonymous FTP archive sites for GNU software. ASIA: ftp.cs.titech.ac.jp, utsun.s.u-tokyo.ac.jp:/ftpsync/prep, cair.kaist.ac.kr:/pub/gnu AUSTRALIA: archie.oz.au:/gnu (archie.oz or archie.oz.au for ACSnet) AFRICA: ftp.sun.ac.za:/pub/gnu MIDDLE-EAST: ftp.technion.ac.il:/pub/unsupported/gnu EUROPE: irisa.irisa.fr:/pub/gnu, grasp1.univ-lyon1.fr:pub/gnu, ftp.mcc.ac.uk, unix.hensa.ac.uk:/pub/uunet/systems/gnu, src.doc.ic.ac.uk:/gnu, ftp.win.tue.nl, ugle.unit.no, ftp.denet.dk, ftp.informatik.rwth-aachen.de:/pub/gnu, ftp.informatik.tu-muenchen.de, ftp.eunet.ch, nic.switch.ch:/mirror/gnu, nic.funet.fi:/pub/gnu, isy.liu.se, ftp.stacken.kth.se, ftp.luth.se:/pub/unix/gnu, archive.eu.net CANADA: ftp.cs.ubc.ca:/mirror2/gnu USA: wuarchive.wustl.edu:/mirrors/gnu, labrea.stanford.edu, ftp.kpc.com:/pub/mirror/gnu, ftp.cs.widener.edu, uxc.cso.uiuc.edu, col.hp.com:/mirrors/gnu, ftp.cs.columbia.edu:/archives/gnu/prep, gatekeeper.dec.com:/pub/GNU, ftp.uu.net:/systems/gnu The "official site" is prep.ai.mit.edu, but your transfer will probably go faster if you use one of the above machines. Most GNU utilities are compressed with "gzip", the GNU compression utility. All GNU archive sites should have a copy of this program, which you will need to uncompress the distributions. UUNET customers can get GNU sources from UUNET via UUCP. UUCP-only sites can get GNU sources by "anonymous UUCP" from site "osu-cis" at Ohio State University. You pay for the long-distance call to OSU; the price isn't too bad on weekends at 9600 bps. Send mail to uucp@cis.ohio-state.edu or osu-cis!uucp for more information. OSU lines are often busy. If you're in the USA, and are willing to spend more money, you can get sources via UUCP from UUNET using their 900 number: 1-900-GOT-SRCS (900 numbers don't work internationally). You will be billed $0.50/minute by your phone company. Don't forget to retrieve libg++ as well! Getting gcc/g++ for the HP Precision Architecture ================================================= If you use the HP Precision Architecture (HP-9000/7xx and HP-9000/8xx) and you want to use debugging, you'll need to grab a special version of GAS from the University of Utah, site jaguar.cs.utah.edu. Look in the "/dist" directory for pa-gas-1.36.u8. A non-standard debug format is used, since HP considers their debug format a trade secret. The GNU debugger, GDB, understands the debug format produced by this version of GAS, but not the format produced by HP's compilers. Some enhancements for the HP that haven't been integrated back into the official GCC are available from the same site in version gcc-2.4.5.u5. The main one seems to be that linking against HPUX shared libraries works. Both sources and precompiled binaries are available from this site for GDB (4.9.u4), GAS (1.36.u8), GCC (2.4.5.u5), and libg++ (2.4.u1). libg++-2.4 requires some patches to install correctly on HP-PA systems. A patched version can be found on jaguar (see above). HP GNU users can also find useful stuff on the site geod.emr.ca in the /pub/GNU-HP directory. Getting gcc/g++ binaries for Solaris 2.x ======================================== "Sun took the C compiler out of Solaris 2.x. Am I stuck?" No; prep.ai.mit.edu and its mirror sites provide GCC binaries for Solaris. As a rule, these binaries are not updated as often as the sources are, so if you want the very latest version of gcc/g++, you may need to grab and install binaries for an older version and use it to bootstrap the latest version from source. The latest gcc binaries on prep.ai.mit.edu and its mirror sites are for version 2.4.5. There are also binaries for "gzip", the GNU compression utility, which you'll need for uncompressing the binary distribution. How do I get a copy of g++ for (some other platform)? ===================================================== The standard gcc/g++ distribution includes VMS support. Since the FSF people don't use VMS, it's likely to be somewhat less solid than the Unix version. Precompiled copies of g++ and libg++ in VMS-installable form are available by FTP from mango.rsmas.miami.edu. DJ Delorie has ported gcc/g++ to MS-DOS; this port is popularly known as "DJGPP" (the P's stand for "plus"). It can be found on many FTP archive sites; its "home" is on omnigate.clarkson.edu, directory ~ftp/pub/msdos/djgpp. Note: omnigate restricts the number of anonymous users. The latest version of DJGPP is 1.10, announced on June 1, 1993. This version is the first that runs under Windows 3.x. It is a port of gcc 2.4.1. FSF sells floppies with DJGPP on them; see above for ordering software from the FSF. For information on Amiga ports of gcc/g++, retrieve the file /pub/gnu/MicrosPorts/Amiga from prep.ai.mit.edu, or write to Markus M. Wild , who I hope won't be too upset that I mentioned his name here. A port of gcc-2.4.1 to the Atari ST can be found on the site "atari.archive.umich.edu", under /atari/Gnustuff/Tos, along with many other GNU programs. See the FAQ for the Usenet group "comp.sys.atari.st" for more information. There are two different ports of gcc-2.3.3 (and g++) to OS/2, the so-called EMX port, which requires a particular Unix emulator, and a port called "gcc/2", which runs native. gcc/2 uses a rather buggy port of the BSD libc. For more information ask around on "comp.os.os2.programmer.misc". gcc/2, together with other GNUware for OS/2, can be obtained by FTP from ftp-os2.nmsu.edu (128.123.35.151) in /pub/os2/2_x/unix/gnu luga.latrobe.edu.au (131.172.2.2) in /pub/os2/2_x/unix/gnu The current maintainer of the gcc/2 port is Colin Jensen (Michael Johnson did the original port). His address is ljensen@netcom.com. Eberhard Mattes did the EMX port. His address is mattes@azu.informatik.uni-stuttgart.de. Because the legal policies of Apple threaten the long-term goals of FSF, as well as the concept of free software, no support will be lent to efforts to port GNU software to Macintosh or other Apple hardware. But I can only find g++-1.42! ============================= "I keep hearing people talking about g++ 2.4.5 (or some other number starting with 2), but the latest version I can find is g++ 1.42. Where is it?" As of gcc 2.0, C, C++, and Objective-C as well are all combined into a single distribution called gcc. If you get gcc you already have g++. The standard installation procedure for any gcc version 2 compiler will install the C++ compiler as well. One could argue that we shouldn't even refer to "g++-2.x.y" but it's a convention. It means "the C++ compiler included with gcc-2.x.y". What is the latest version of gcc, g++, and libg++? =================================================== The latest "2.x" version of gcc/g++ is 2.4.5, released June 20, 1993. The latest version of libg++ is 2.4, released June 29, 1993. For some non-Unix platforms, 2.2.2 may be the latest compiler that has been ported. libg++ 2.3 (and later versions) will not compile with gcc-2.2.2; use libg++ 2.2 instead. The latest "1.x" version of gcc is 1.42, and the latest "1.x" version of g++ is 1.42.0. While gcc 1.42 is quite usable for C programs, I recommend against using g++ 1.x except in special circumstances. Installation Issues and Problems ******************************** I can't build g++ 1.x.y with gcc-2.x.y! ======================================= "I obtained gcc-2.x.y and g++ 1.x.y and I'm trying to build it, but I'm having major problems. What's going on?" If you wish to build g++-1.42, you must obtain gcc-1.42 first. The installation instructions for g++ version 1 leave a lot to be desired, unfortunately, and I would recommend that, unless you have a special reason for needing the 1.x compiler, that C++ users use the latest g++-2.x version, as it is the version that is being actively maintained. There is no template support in g++-1.x, and it is generally much further away from the ANSI draft standard than g++-2.x is. OK, I've obtained gcc; what else do I need? =========================================== First off, you'll want libg++ as you can do almost nothing without it (unless you replace it with some other class library). Second, depending on your platform, you may need "gas", the GNU assembler, or the GNU linker (see next question). Finally, while it is not required, you'll almost certainly want the GNU debugger, gdb. The latest version is 4.9, released May 12, 1993. Other debuggers (like dbx, for example) will normally not be able to understand at least some of the debug information produced by g++. Should I use the GNU linker, or should I use "collect"? ======================================================= First off, for novices: special measures must be taken with C++ to arrange for the calling of constructors for global or static objects before the execution of your program, and for the calling of destructors at the end. (Exception: System VR3 and System VR4 linkers support user-defined segments; g++ on these systems requires neither the GNU linker nor collect. So if you have such a system, the answer is that you don't need either one). If you have experience with AT&T's "cfront", this function is performed there by programs named "patch" or "munch". With GNU C++, it is performed either by the GNU linker or by a program known as "collect". The collect program is part of the gcc-2.x distribution; you can obtain the GNU linker separately as part of the "binutils" package. The latest version of binutils is 2.2.1, released May 21, 1993. (To be technical, it's "collect2"; there were originally several alternative versions of collect, and this is the one that survived). There are advantages and disadvantages to either choice. Advantages of the GNU linker: It's faster than using collect - collect basically runs the standard Unix linker on your program twice, inserting some extra code after the first pass to call the constructors. This is a sizable time penalty for large programs. The GNU linker does not require this extra pass. GNU ld reports undefined symbols using their true names, not the mangled names. If there are undefined symbols, GNU ld reports which object file(s) refer to the undefined symbol(s). As of binutils version 2.2, on systems that use the so-called "a.out" debug format (e.g. Suns running SunOS 4.x), the GNU linker compresses the debug symbol table considerably, which in at least some cases may make up, in disk space, for its inability to use shared libraries. Advantages of collect: If your native linker supports shared libraries, you can use shared libraries with collect. The GNU linker does not (yet) support shared libraries. Note: using existing shared libraries (X and libc, for example) works very nicely; generating shared libraries from g++-compiled code is another matter, generally requiring OS-dependent tricks if it is possible at all. The GNU linker has not been ported to as many platforms as g++ has, so you may be forced to use collect. If you use collect, you don't need to get something extra and figure out how to install it; the standard gcc installation procedure will do it for you. In conclusion, I don't see a clear win for either alternative at this point. Take your pick. Should I use the GNU assembler, or my vendor's assembler? ========================================================= This depends on your platform and your decision about the GNU linker. For most platforms, you'll need to use gas if you use the GNU linker. For some platforms, you have no choice; check the gcc installation notes to see whether you must use gas. But you can usually use the vendor's assembler if you don't use the GNU linker. The GNU assembler assembles faster than many native assemblers; however, on many platforms it cannot support the local debugging format. Should I use the GNU C library? =============================== At this point in time, no. The GNU C library is still very young, and libg++ still conflicts with it in some places. Use your native C library unless you know a lot about the gory details of libg++ and gnu-libc. This will probably change in the future. Problems building libg++ on 386/486 =================================== Attempts to install libg++ on 386 or 486 systems running ports of SVR4 have problems because of bugs in debugging support on that platform. Briefly, debugging does not currently work right yet for C++. You should be able to build the library successfully by deleting the -g flag from the Makefiles (this should no longer be necessary with gcc 2.4.x although debugging still doesn't work). See the section entitled "Debugging on SVR4 systems." Other problems building libg++ ============================== "I am having trouble building libg++. Help!" On some platforms (for example, Ultrix), you may see errors complaining about being unable to open dummy.o. On other platforms (for example, SunOS), you may see problems having to do with the type of size_t. The fix for these problems is to make libg++ by saying "make CC=gcc". According to Per Bothner, it should no longer be necessary to specify "CC=gcc" for libg++-2.3.1 or later. "I built and installed libg++, but g++ can't find it. Help!" The string given to `configure' that identifies your system must be the same when you install libg++ as it was when you installed gcc. Also, if you used the `--prefix' option to install gcc somewhere other than `/usr/local', you must use the same value for `--prefix' when installing libg++, or else g++ will not be able to find g++. But I'm *still* having problems with `size_t'! ============================================== "I did all that, and I'm *still* having problems with disagreeing definitions of size_t, SIZE_TYPE, and the type of functions like `strlen'." The problem may be that you have an old version of `_G_config.h' lying around. As of libg++ version 2.4, `_G_config.h', since it is platform-specific, is inserted into a different directory; most include files are in `$prefix/lib/g++-include', but this file now lives in `$prefix/$arch/include'. If, after upgrading your libg++, you find that there is an old copy of `_G_config.h' left around, remove it, otherwise g++ will find the old one first. Do I need to rebuild libg++ to go with my new g++? ================================================== "After I upgraded g++ to the latest version, I'm seeing undefined symbols." or "If I upgrade to a new version of g++, do I need to reinstall libg++?" This depends; as a rule, some upgrades will require rebuilding libg++ and others will not. Both versions 2.3.3 and 2.4.0 introduced some incompatibilities with previous versions. For 2.3.3, the name mangling of certain virtual table names changed, which introduced an incompatiblity. For 2.4.0, the type of "size_t" changed on Suns from int (as declared by the include files provided by Sun) to unsigned long (the ANSI C and draft ANSI C++ standards declare that size_t must be unsigned, and the GCC maintainers are now correcting this "bug"). Conclusion: if your old compiler is an older version than 2.3.3, you must rebuild libg++ when you install a new g++. If your vendor declares size_t to be a signed type and your old compiler is an older version than 2.4.0, you also must rebuild libg++. This would be a good opportunity to upgrade to the libg++ 2.4 release if you haven't yet, to minimize the amount of rebuilding. User Problems ************* Linker reports undefined symbols for static data members ======================================================== "g++ reports undefined symbols for all my static data members when I link, even though the program works correctly for compiler XYZ. What's going on?" The problem is almost certainly that you don't give definitions for your static data members. If you have class Foo { ... void method(); static int bar; }; you have only declared that there is an int named Foo::bar and a member function named Foo::method that is defined somewhere. You still need to defined BOTH method() and bar in some source file. According to the draft ANSI standard, you must supply an initializer, such as int Foo::bar = 0; in one (and only one) source file. g++ won't accept the placement new syntax. ========================================== "I have a program that uses the "placement syntax" of operator new, e.g. new (somewhere) T; and g++ won't accept it." Up until version 2.3.1, g++ accepted an alternate form of the placement syntax, for historical reasons; use new {somewhere} T; if you are using g++-2.2.2 or older. As of 2.3.1, g++ finally fixed this, using the standard ARM syntax for "placement new". A few remaining glitches were fixed in 2.3.2. The only remaining problem is with declarators for pointers to functions; new (void (*)(int)); // confuses gcc 2.3.2 new (a) (void (*)(int)); // ditto These can be worked around with a typedef: typedef void (*fun)(int); new fun; new (a) fun; I think I have found a bug in g++. ================================== "I think I have found a bug in g++, but I'm not sure. How do I know, and who should I tell?" First, see the excellent section on bugs and bug reports in the gcc manual (which is included in the gcc distribution). As a short summary of that section: if the compiler gets a fatal signal, for any input, it's a bug (newer versions of g++ will ask you to send in a bug report when they detect an error in themselves). Same thing for producing invalid assembly code. When you report a bug, make sure to describe your platform (the type of computer, and the version of the operating system it is running) and the version of the compiler that you are running. Also provide enough code so that the g++ maintainers can duplicate your bug. I will add some extra notes that are C++-specific, since the notes from gcc are generally C-specific. First, mail your bug report to "bug-g++@prep.ai.mit.edu". You may also post to gnu.g++.bug, but it's better to use mail, particularly if you have any doubt as to whether your news software generates correct reply addresses. Don't mail C++ bugs to bug-gcc@prep.ai.mit.edu. If your bug involves libg++ rather than the compiler, mail to bug-lib-g++@prep.ai.mit.edu. If you're not sure, choose one, and if you guessed wrong, the maintainers will forward it to the other list. Second, if your program does one thing, and you think it should do something else, it is best to consult a good reference if in doubt. The standard reference is "The Annotated C++ Reference Manual", by Ellis and Stroustrup (copyright 1990, ISBN #0-201-51459-1). This is what they're talking about on the net when they refer to "the ARM". The reference manual, without annotations, also appears in Stroustrup's "The C++ Programming Language, Second Edition" (copyright 1991, ISBN #0-201-53992-6). Both books are published by Addison-Wesley. Note that the behavior of (any version of) AT&T's "cfront" compiler is NOT the standard for the language. Porting programs from other compilers to g++ ============================================ "I have a program that runs on , and I want to get it running under g++. Is there anything I should watch out for?" First, see the questions on placement new syntax and static data members. There are two other reasons why a program that worked under one compiler might fail under another: your program may depend on the order of evaluation of side effects in an expression, or it may depend on the lifetime of a temporary (you may be assuming that a temporary object "lives" longer than the standard guarantees). As an example of the first: void func(int,int); int i = 3; func(i++,i++); Novice programmers think that the increments will be evaluated in strict left-to-right order. Neither C nor C++ guarantees this; the second increment might happen first, for example. func might get 3,4, or it might get 4,3. The second problem often happens with classes like the libg++ String class. Let's say I have String func1(); void func2(const char*); and I say func2(func1()); because I know that class String has an "operator const char*". So what really happens is func2(func1().convert()); where I'm pretending I have a convert() method that is the same as the cast. This is unsafe, because the temporary String object may be deleted after its last use (the call to the conversion function), leaving the pointer pointing to garbage, so by the time func2 is called, it gets an invalid argument. If you think this is ugly, you should know that the ANSI C++ committee is still debating the lifetime-of-temporaries problem. For now, the safe way to write such code is to give the temporary a name, which forces it to live until the end of the scope of the name. For example: String& tmp = func1(); func2(tmp); Finally, like all compilers (but especially C++ compilers, it seems), g++ has bugs, and you may have tweaked one. Why does g++ mangle names differently from other C++ compilers? =============================================================== See the answer to the next question. Why can't g++ code link with code from other C++ compilers? =========================================================== "Why can't I link g++-compiled programs against libraries compiled by some other C++ compiler?" Some people think that, if only the FSF and Cygnus Support folks would stop being stubborn and mangle names the same way that, say, cfront does, then any g++-compiled program would link successfully against any cfront-compiled library and vice versa. Name mangling is the least of the problems. Compilers differ as to how objects are laid out, how multiple inheritance is implemented, how virtual function calls are handled, and so on, so if the name mangling were made the same, your programs would link against libraries provided from other compilers but then crash when run. For this reason, the ARM *encourages* compiler writers to make their name mangling different from that of other compilers for the same platform. Incompatible libraries are then detected at link time, rather than at run time. What documentation exists for g++ 2.x? ====================================== Relatively little. The gcc manual describes the C front end, and also the back end, which is shared by the C++ compiler, but there is relatively little documentation for the C++ front end beyond a cursory description of the command line options (although more C++ specific information has been added to the gcc manual as of version 2.4.1). There is a Unix-style manual entry, "g++.1", in the gcc-2.x distribution; this describes the extra command-line options that g++ supports, and the #pragma interface and #pragma implementation directives. (Latest news: as of 2.4.0, these pragmas are finally described in the main gcc manual). A draft of a document describing the g++ internals appears in the gcc distribution (called g++int.texi); it is still incomplete. What are the differences between g++ and the ARM specification of C++? ====================================================================== The chief thing missing from g++ that is in the ARM is exceptions. There are bits and pieces of exception code present, but it is not presently usable. The template implementation is still new. The implementation in 2.4.1 represents a considerable improvement over that of previous releases, but it has a long way to go. g++ does not implement a separate pass to instantiate template functions and classes at this point; for this reason, it will not work, for the most part, to declare your template functions in one file and define them in another. The compiler will need to see the entire definition of the function, and will generate a static copy of the function in each file in which it is used. As with any beta-test compiler, there are bugs. You can help improve the compiler by submitting detailed bug reports. One of the weakest areas of g++ other than templates is the resolution of overloaded functions and operators in complex cases. The usual symptom is that in a case where the ARM says that it is ambiguous which function should be chosen, g++ chooses one (often the first one declared). This is usually not a problem when porting C++ code from other compilers to g++, but shows up as errors when code developed under g++ is ported to other compilers. [A full bug list would be very long indeed, so I won't put one here. I may add a list of frequently-reported bugs and "non-bugs" like the static class members issue mentioned above]. Will g++ compile InterViews? The NIH class library? ==================================================== The NIH class library uses a non-portable, compiler-dependent hack to initialize itself, which makes life difficult for g++ users. It will not work without modification, and I don't know what modifications are required or whether anyone has done them successfully. Brendan Kehoe of Cygnus Support is working on getting NIHCL to build with g++. He says, "The NIHCL release will hopefully contain patches to gcc to let it build." [ From Steinar Bang ] InterViews 3.1 compiles and runs with gcc-2.3.3 and libg++-2.3, except that the "doc" application immediately dumps core when you try to run it. There is also a small glitch with idraw. There is a patch for InterViews 3.1 from Johan Garpendahl available for FTP from site "ugle.unit.no". It is in the file /pub/X11/contrib/InterViews/g++/3.1-beta3-patch. This fixes two things: the Doc coredump, and the pattern menu of idraw. Read the instructions at the start of the file. [ I don't know whether the situation has changed with 2.4.0 ] Debugging on SVR4 systems ========================= "When I use the -g flag on C++ code on a System V Release 4 system, I get lots of undefined symbols at link time. Why? Help!" [From Ron Guilmette:] The changes needed to get the g++ front-end to generate proper DWARF style debugging information for System V Release 4 are not yet completed, nor will they be until g++ version 2.4 (at the earliest). (Guess what? 2.4 is out, and it *still* doesn't work, but now g++ will give you a warning message and turn off debugging rather than put out bogus assembly code. Latest word from Brendan Kehoe: "it should work [better] in whatever major release comes after 2.4.1 ..."). [Ron again:] There is nothing that you (as an end-user) can do to correct this problem. (It is actually *many* problems, and they are all very complex.) Until the g++ maintainers have time to fix this, you should simply *avoid* using the -g option when using g++ on SVR4. What are the rules for shipping code built with g++ and libg++? *************************************************************** "Is it is possible to distribute programs for profit that are created with g++ and use the g++ libraries?" I am not a lawyer, and this is not legal advice. In any case, I have little interest in telling people how to violate the spirit of the GNU licenses without violating the letter. This section tells you how to comply with the intention of the GNU licenses as best I understand them. The FSF has no objection to your making money. Its only interest is that source code to their programs, and libraries, and to modified versions of their programs and libraries, is always available. The short answer is that you do not need to release the source to your program, but you can't just ship a stripped executable either. Compiling your code with a GNU compiler does not affect its copyright; it is still yours. However, in order to ship code that links in a GNU library such as libg++ there are certain rules you must follow. The rules are described in the file COPYING.LIB that accompanies gcc distributions; it is also included in the libg++ distribution. See that file for the exact rules. The agreement is called the Library GNU Public License or LGPL. It is much "looser" than the GNU Public License, or GPL, that covers must GNU programs. Here's the deal: let's say that you use some version of libg++, completely unchanged, in your software, and you want to ship only a binary form of your code. You can do this, but there are several special requirements. If you want to use libg++ but ship only object code for your code, you have to ship source for libg++ (or ensure somehow that your customer already has the source for the exact version you are using), and ship your application in linkable form. You cannot forbid your customer from reverse-engineering or extending your program by exploiting its linkable form. Furthermore, if you modify libg++ itself, you must provide source for your modifications (making a derived class does not count as modifying the library - that is "a work that uses the library"). Concept Index ************* -- Joe Buck jbuck@ohm.EECS.Berkeley.EDU