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5 <META NAME="DESCRIPTION" CONTENT="FAQ for the GNU libstdc++ effort.">
6 <TITLE>libstdc++-v3 FAQ</TITLE>
7 <LINK REL=StyleSheet HREF="../lib3styles.css">
9 ** Locations of "the most recent snapshot is the Nth" text are
10 ** answers 1_1, 1_4, 4_1, 5_6.
12 <!-- $Id: index.html,v 1.9 2001/05/30 21:55:04 pme Exp $ -->
16 <H1 CLASS="centered">libstdc++ Frequently Asked Questions</H1>
18 <P>The latest version of this document is always available at
19 <A HREF="http://gcc.gnu.org/onlinedocs/libstdc++/faq/">
20 http://gcc.gnu.org/onlinedocs/libstdc++/faq/</A>.</P>
22 <P>To the <A HREF="http://gcc.gnu.org/libstdc++/">libstdc++-v3 homepage</A>.
24 <!-- ####################################################### -->
28 <LI><A HREF="#1_0">General Information</A>
29 <!-- I suspect these will mostly be links to/into existing documents. -->
31 <LI><A HREF="#1_1">What is libstdc++-v3?</A>
32 <LI><A HREF="#1_2">Why should I use libstdc++?</A>
33 <LI><A HREF="#1_3">Who's in charge of it?</A>
34 <LI><A HREF="#1_4">How do I get libstdc++?</A>
35 <LI><A HREF="#1_5">When is libstdc++ going to be finished?</A>
36 <LI><A HREF="#1_6">How do I contribute to the effort?</A>
37 <LI><A HREF="#1_7">What happened to libg++? I need that!</A>
38 <LI><A HREF="#1_8">What if I have more questions?</A>
41 <LI><A HREF="#2_0">Installation</A>
43 <LI><A HREF="#2_1">How do I install libstdc++-v3?</A>
44 <LI><A HREF="#2_2">[removed]</A>
45 <LI><A HREF="#2_3">What is this CVS thing that you keep
47 <LI><A HREF="#2_4">How do I know if it works?</A>
50 <LI><A HREF="#3_0">Platform-Specific Issues</A>
52 <LI><A HREF="#3_1">Can libstdc++-v3 be used with <my
53 favorite compiler>?</A>
54 <LI><A HREF="#3_2">[removed]</A>
55 <LI><A HREF="#3_3">Building under DEC OSF kills the assembler</A>
58 <LI><A HREF="#4_0">Known Bugs and Non-Bugs</A>
60 <LI><A HREF="#4_1">What works already?</A>
61 <LI><A HREF="#4_2">Bugs in gcc/g++ (not libstdc++-v3)</A>
62 <LI><A HREF="#4_3">Bugs in the C++ language/lib specification</A>
63 <LI><A HREF="#4_4">Things in libstdc++ that look like bugs</A>
65 <LI><A HREF="#4_4_Weff">-Weffc++ complains too much</A>
66 <LI><A HREF="#4_4_rel_ops">"ambiguous overloads"
67 after including an old-style header</A>
68 <LI><A HREF="#4_4_interface">The g++-3 headers are
69 <STRONG>not ours</STRONG></A>
70 <LI><A HREF="#4_4_glibc">compilation errors from streambuf.h</A>
71 <LI><A HREF="#4_4_checks">errors about <EM>*Cconcept</EM> and
72 <EM>constraints</EM> in the STL...</A>
74 <LI><A HREF="#4_5">Aw, that's easy to fix!</A>
77 <LI><A HREF="#5_0">Miscellaneous</A>
79 <LI><A HREF="#5_1">string::iterator is not char*;
80 vector<T>::iterator is not T*</A>
81 <LI><A HREF="#5_2">What's next after libstdc++-v3?</A>
82 <LI><A HREF="#5_3">What about the STL from SGI?</A>
83 <LI><A HREF="#5_4">Extensions and Backward Compatibility</A>
84 <LI><A HREF="#5_5">[removed]</A>
85 <LI><A HREF="#5_6">Is libstdc++-v3 thread-safe?</A>
86 <LI><A HREF="#5_7">How do I get a copy of the ISO C++ Standard?</A>
93 <!-- ####################################################### -->
95 <H1><A NAME="1_0">1.0 General Information</A></H1>
96 <!-- I suspect these will mostly be links to/into existing documents. -->
97 <H2><A NAME="1_1">1.1 What is libstdc++-v3?</A></H2>
98 <P>The GNU Standard C++ Library v3, or libstdc++-2.9x, is an
99 ongoing project to implement the ISO 14882 Standard C++ library
100 as described in chapters 17 through 27 and annex D. As the
101 library reaches stable plateaus, it is captured in a snapshot
102 and released. The current release is <A
103 HREF="ftp://gcc.gnu.org/pub/libstdc++/libstdc++-2.92.tar.gz">the
104 eleventh snapshot</A>. For those who want to see exactly how
105 far the project has come, or just want the latest
106 bleeding-edge code, the up-to-date source is available over
107 anonymous CVS, and can even be browsed over the Web (see below).
109 <P>A more formal description of the V3 goals can be found in the
110 official <A HREF="../17_intro/DESIGN">design document</A>.
114 <H2><A NAME="1_2">1.2 Why should I use libstdc++?</A></H2>
115 <P>The completion of the ISO C++ standardization gave the
116 C++ community a powerful set of reuseable tools in the form
117 of the C++ Standard Library. However, all existing C++
118 implementations are (as the Draft Standard used to say)
119 "incomplet and incorrekt," and many suffer from
120 limitations of the compilers that use them.
122 <P>The GNU C/C++/FORTRAN/<pick-a-language> compiler
123 (<TT>gcc</TT>, <TT>g++</TT>, etc) is widely considered to be
124 one of the leading compilers in the world. Its development
125 has recently been taken over by the
126 <A HREF="http://gcc.gnu.org/">GCC team</A>. All of
127 the rapid development and near-legendary
129 HREF="http://gcc.gnu.org/gcc-2.95/buildstat.html">portability</A>
130 that are the hallmarks of an open-source project are being
131 applied to libstdc++.
133 <P>That means that all of the Standard classes and functions
134 (such as <TT>string</TT>, <TT>vector<></TT>, iostreams,
135 and algorithms) will be freely available and fully compliant.
136 Programmers will no longer need to "roll their own"
137 nor be worried about platform-specific incompatabilities.
141 <H2><A NAME="1_3">1.3 Who's in charge of it?</A></H2>
142 <P>The libstdc++ project is contributed to by several developers
143 all over the world, in the same way as GCC or Linux.
144 Benjamin Kosnik, Gabriel Dos Reis, Phil Edwards, and Ulrich
145 Drepper are the lead maintainers of the CVS archive.
147 <P>Development and discussion is held on the libstdc++ mailing
148 list. Subscribing to the list, or searching the list
149 archives, is open to everyone. You can read instructions for
150 doing so on the <A HREF="http://gcc.gnu.org/libstdc++/">homepage</A>.
151 If you have questions, ideas, code, or are just curious, sign up!
155 <H2><A NAME="1_4">1.4 How do I get libstdc++?</A></H2>
156 <P>The eleventh (and latest) snapshot of libstdc++-v3 is <A
157 HREF="ftp://gcc.gnu.org/pub/libstdc++/libstdc++-2.92.tar.gz">
158 available via ftp</A>.
160 <P>The <A HREF="http://gcc.gnu.org/libstdc++/">homepage</A>
161 has instructions for retrieving the latest CVS sources, and for
162 browsing the CVS sources over the web.
164 <P>The subset commonly known as the Standard Template Library
165 (chapters 23 through 25, mostly) is adapted from the SGI STL,
166 which is also an ongoing work.<!-- Possibly a link to SGI's
171 <H2><A NAME="1_5">1.5 When is libstdc++ going to be finished?</A></H2>
172 <!-- <P>Nathan Myers gave the best of all possible answers in <A
173 HREF="http://www.deja.com/getdoc.xp?AN=469581698&fmt=text">a
174 Usenet article</A>.</P>
175 which is no longer available, thanks deja...-->
176 <P>Nathan Myers gave the best of all possible answers, responding to a
177 Usenet article asking this question: <EM>Sooner, if you help.</EM>
182 <H2><A NAME="1_6">1.6 How do I contribute to the effort?</A></H2>
183 <P>Here is <A HREF="../17_intro/contribute.html">a
184 page devoted to this topic</A>. Subscribing to the mailing
185 list (see above, or the homepage) is a very good idea if you
186 have something to contribute, or if you have spare time and
187 want to help. Contributions don't have to be in the form of
188 source code; anybody who is willing to help write
189 documentation, for example, or has found a bug in code that
190 we all thought was working, is more than welcome!
194 <H2><A NAME="1_7">1.7 What happened to libg++? I need that!</A></H2>
195 <P>The most recent libg++ README states that libg++ is no longer
196 being actively maintained. It should not be used for new
197 projects, and is only being kicked along to support older code.
199 <P>The libg++ was designed and created when there was no Standard
200 to provide guidance. Classes like linked lists are now provided
201 for by <TT>list<T></TT> and do not need to be created by
202 <TT>genclass</TT>. (For that matter, templates exist now and
203 are well-supported, whereas genclass (mostly) predates them.)
205 <P>There are other classes in libg++ that are not specified in the
206 ISO Standard (e.g., statistical analysis). While there are a
207 lot of really useful things that are used by a lot of people
208 (e.g., statistics :-), the Standards Committee couldn't include
209 everything, and so a lot of those "obvious" classes
212 <P>Since libstdc++ is an implementation of the Standard Library, we
213 have no plans at this time to include non-Standard utilities
214 in the implementation, however handy they are. (The extensions
215 provided in the SGI STL aren't maintained by us and don't get
216 a lot of our attention, because they don't require a lot of our
217 time.) It is entirely plausable that the "useful stuff"
218 from libg++ might be extracted into an updated utilities library,
219 but nobody has stated such a project yet.
221 <!-- The advertisement, so to speak, might have to go. Hmmmmm. -->
222 <P>(The <A HREF="http://www.boost.org/">Boost</A> site houses free
223 C++ libraries that do varying things, and happened to be started
224 by members of the Standards Committee. Certain "useful
225 stuff" classes will probably migrate there.)
227 <P>For the bold and/or desperate, the
228 <A HREF="http://gcc.gnu.org/fom_serv/cache/33.html">GCC FAQ</A>
229 describes where to find the last libg++ source.
233 <H2><A NAME="1_8">1.8 What if I have more questions?</A></H2>
234 <P>If you have read the README and RELEASE-NOTES files, and your
235 question remains unanswered, then just ask the mailing list.
236 At present, you do not need to be subscribed to the list to
237 send a message to it. More information is available on the
238 homepage (including how to browse the list archives); to send
239 to the list, use <A HREF="mailto:libstdc++@gcc.gnu.org">
240 <CODE>libstdc++@gcc.gnu.org</CODE></A>.
242 <P>If you have a question that you think should be included here,
243 or if you have a question <EM>about</EM> a question/answer here,
244 contact <A HREF="mailto:pme@gcc.gnu.org">Phil Edwards</A>
245 or <A HREF="mailto:gdr@gcc.gnu.org">Gabriel Dos Reis</A>.
250 <H1><A NAME="2_0">2.0 Installation</A></H1>
251 <H2><A NAME="2_1">2.1 How do I install libstdc++-v3?</A></H2>
252 <P>Complete instructions are not given here (this is a FAQ, not
253 an installation document), but the tools required are few:
256 <LI> A 3.x release of GCC. Note that building GCC is much
257 easier and more automated than building the GCC 2.[78]
258 series was. If you are using GCC 2.95, you can still
259 build earlier snapshots of libstdc++.
260 <LI> GNU Make is recommended, but should not be required.
261 <LI> The GNU Autotools are needed if you are messing with
262 the configury or makefiles.
264 <P>The file <A HREF="../documentation.html">documentation.html</A>
265 provides a good overview of the steps necessary to build, install,
266 and use the library. Instructions for configuring the library
267 with new flags such as --enable-threads are there also, as well as
268 patches and instructions for working with GCC 2.95.
270 <P>The top-level install.html and
271 <A HREF="../17_intro/RELEASE-NOTES">RELEASE-NOTES</A> files contain
272 the exact build and installation instructions. You may wish to
273 browse those files over CVSweb ahead of time to get a feel for
274 what's required. RELEASE-NOTES is located in the
275 ".../docs/17_intro/" directory of the distribution.
279 <H2><A NAME="2_2">2.2 [removed]</A></H2>
280 <P>This question has become moot and has been removed. The stub
281 is here to preserve numbering (and hence links/bookmarks).
285 <H2><A NAME="2_3">2.3 What is this CVS thing that you
286 keep mentioning?</A></H2>
287 <P>The <EM>Concurrent Versions System</EM> is one of several revision
288 control packages. It was selected for GNU projects because it's
289 free (speech), free (beer), and very high quality. The <A
290 HREF="http://www.gnu.org/software/cvs/cvs.html">CVS entry in
291 the GNU software catalogue</A> has a better description as
293 <A HREF="http://www.cvshome.org/">link to the makers of CVS</A>.
295 <P>The "anonymous client checkout" feature of CVS is
296 similar to anonymous FTP in that it allows anyone to retrieve
297 the latest libstdc++ sources.
299 <P>After the first of April, American users will have a
300 "/pharmacy" command-line option...
301 <!-- wonder how long that'll live -->
305 <H2><A NAME="2_4">2.4 How do I know if it works?</A></H2>
306 <P>libstdc++-v3 comes with its own testsuite. You do not need
307 to actually install the library ("<TT>make
308 install</TT>") to run the testsuite.
310 <P>To run the testsuite on the library after building it, use
311 "make check" while in your build directory. To run
312 the testsuite on the library after building and installing it,
313 use "make check-install" instead.
315 <P>If you find bugs in the testsuite programs themselves, or if
316 you think of a new test program that should be added to the
317 suite, <B>please</B> write up your idea and send it to the list!
321 <H1><A NAME="3_0">3.0 Platform-Specific Issues</A></H1>
322 <H2><A NAME="3_1">3.1 Can libstdc++-v3 be used with <my
323 favorite compiler>?</A></H2>
324 <P>Probably not. Yet.</P>
325 <P>Because GCC advances so rapidly, development and testing of
326 libstdc++ is being done almost entirely under that compiler.
327 If you are curious about whether other, lesser compilers
328 (*grin*) support libstdc++, you are more than welcome to try.
329 Configuring and building the library (see above) will still
330 require certain tools, however. Also keep in mind that
331 <EM>building</EM> libstdc++ does not imply that your compiler
332 will be able to <EM>use</EM> all of the features found in the
333 C++ Standard Library.
335 <P>Since the goal of ISO Standardization is for all C++
336 implementations to be able to share code, the final libstdc++
337 should, in theory, be useable under any ISO-compliant
338 compiler. It will still be targeted and optimized for
343 <H2><A NAME="3_2">3.2 [removed]</A></H2>
344 <P>This question has become moot and has been removed. The stub
345 is here to preserve numbering (and hence links/bookmarks).
349 <H2><A NAME="3_3">3.3 Building DEC OSF kills the assembler</A></H2>
350 <P>The <TT>atomicity.h</TT> header for the Alpha processor
351 currently uses pseudo-operators which the DEC assembler
352 doesn't understand (in particular, .subsection and .previous).
353 The simple solution is to install GNU <TT>as</TT> and arrange
354 for the GCC build to use it (or merge the sources and build
355 it during the bootstrap).
358 <A HREF="http://gcc.gnu.org/ml/libstdc++/2000-12/msg00279.html">knows
359 the DEC assembler well enough</A> to provide the equivalent of
360 these two pseudos would win praise and accolades from many.
365 <H1><A NAME="4_0">4.0 Known Bugs and Non-Bugs</A></H1>
366 <EM>Note that this section can get rapdily outdated -- such is the
367 nature of an open-source project. For the latest information, join
368 the mailing list or look through recent archives. The RELEASE-
369 NOTES and BUGS files are generally kept up-to-date.</EM>
371 <H2><A NAME="4_1">4.1 What works already?</A></H2>
372 <P>This is a verbatim clip from the "Status" section
373 of the RELEASE-NOTES for the latest snapshot.
376 <!-- Yeah, I meant that "verbatim clip" thing literally... :-) -->
381 - preliminary doxygen documentation has been added. Running "make
382 doxygen" in the libstdc++-v3 build directory will generate HTML
383 documentation that can be used to cross-reference names and files in
385 - a dejagnu based testing framework has been added
386 - a new implementation of the concept checking code has been ported
387 from the boost libraries.
388 - support for -fno-exceptions has been added
389 - stdexcept was re-written
390 - using deprecated or antiquated headers now gives a warning
391 - the stdio interface to iostreams has been tweaked, and now works
392 with synchronized c/c++ io
393 - new libsupc++ routines implementing the IA-64 C++ ABI.
394 - HPUX configuration files
395 - support for AIX added
396 - a lot of bugs were fixed.
397 - preliminary named locales implemented
398 - portability improvements made to generation of <limits>
399 - speedups to improve configuration time.
400 - DJGPP support added.
401 - support for dlopening shared libstdc++
406 <H2><A NAME="4_2">4.2 Bugs in gcc/g++ (not libstdc++-v3)</A></H2>
407 <P>This is by no means meant to be complete nor exhaustive, but
408 mentions some problems that users may encounter when building
409 or using libstdc++. If you are experiencing one of these
410 problems, you can find more information on the libstdc++ and
411 the GCC mailing lists.
414 <LI>As of 2.91, these bugs have all been fixed. We look forward
415 to new ones, well, not exactly...
419 <H2><A NAME="4_3">4.3 Bugs in the C++ language/lib specification</A></H2>
420 <P>Yes, unfortunately, there are some. In a <A
421 HREF="http://gcc.gnu.org/ml/libstdc++/1998/msg00006.html">message
422 to the list</A>, Nathan Myers announced that he has started a list of
423 problems in the ISO C++ Standard itself, especially with
424 regard to the chapters that concern the library. The list
426 HREF="http://www.cantrip.org/draft-bugs.txt">posted on his
427 website</A>. Developers who are having problems interpreting
428 the Standard may wish to consult his notes.
430 <P>For those people who are not part of the ISO Library Group
431 (i.e., nearly all of us needing to read this page in the first
432 place :-), a public list of the library defects is occasionally
433 published <A HREF="http://anubis.dkuug.dk/jtc1/sc22/wg21/">here</A>.
437 <H2><A NAME="4_4">4.4 Things in libstdc++ that look like bugs</A></H2>
438 <P>There are things which are not bugs in the compiler (4.2) nor
439 the language specification (4.3), but aren't really bugs in
440 libstdc++, either. Really! Please do not report these as bugs.
443 <P><STRONG>-Weffc++</STRONG>
444 The biggest of these is the quadzillions of warnings about the
445 library headers emitted when <TT>-Weffc++</TT> is used. Making
446 libstdc++ "-Weffc++-clean" is not a goal of the project,
447 for a few reasons. Mainly, that option tries to enforce
448 object-oriented programming, while the Standard Library isn't
449 necessarily trying to be OO. There are multiple solutions
453 <A NAME="4_4_rel_ops">
454 <P><STRONG>rel_ops</STRONG>
455 Another is the <TT>rel_ops</TT> namespace and the template
456 comparison operator functions contained therein. If they become
457 visible in the same namespace as other comparison functions
458 (e.g., '<TT>using</TT>' them and the <iterator> header),
459 then you will suddenly be faced with huge numbers of ambiguity
460 errors. This was discussed on the -v3 list; Nathan Myers
461 <A HREF="http://gcc.gnu.org/ml/libstdc++/2001-01/msg00247.html">sums
465 <A NAME="4_4_interface"><H3>The g++-3 headers are
466 <EM>not ours</EM></H3>
467 <P>If you have found an extremely broken header file which is
468 causing problems for you, look carefully before submitting a
469 "high" priority bug report (which you probably shouldn't
470 do anyhow; see the last paragraph of the page describing
471 <A HREF="http://gcc.gnu.org/gnatswrite.html">the GCC bug database</A>).
473 <P>If the headers are in <CODE>${prefix}/include/g++-3</CODE>, then
474 you are using the old libstdc++-v2 library, which is nonstandard
475 and unmaintained. Do not report problems with -v2 to the -v3
478 <P>Currently our header files are installed in
479 <CODE>${prefix}/include/g++-v3</CODE> (see the 'v'?). This may
480 change with the next release of GCC, as it may be too confusing,
481 but <A HREF="http://gcc.gnu.org/ml/gcc/2000-10/msg00732.html">the
482 question has not yet been decided</A>.
486 <P><STRONG>glibc</STRONG>
487 If you're on a GNU/Linux system and have just upgraded to
488 glibc 2.2, but are still using gcc 2.95.2, then you should have
489 read the glibc FAQ, specifically 2.34:
491 2.34. When compiling C++ programs, I get a compilation error in streambuf.h.
493 {BH} You are using g++ 2.95.2? After upgrading to glibc 2.2, you need to
494 apply a patch to the include files in /usr/include/g++, because the fpos_t
495 type has changed in glibc 2.2. The patch is at
496 http://clisp.cons.org/~haible/gccinclude-glibc-2.2-compat.diff
498 Note that 2.95.x shipped with the
499 <A HREF="#4_4_interface">old v2 library</A> which is no longer
500 maintained. Also note that gcc 2.95.3 fixes this problem, but
501 requires a separate patch for libstdc++-v3.
504 <A NAME="4_4_checks">
505 <P><STRONG>concept checks</STRONG>
506 If you see compilation errors containing messages about
507 <TT> <EM>foo</EM>Concept </TT>and a<TT> constraints </TT>
508 member function, then most likely you have violated one of the
509 requirements for types used during instantiation of template
510 containers and functions. For example, EqualityComparableConcept
511 appears if your types must be comparable with == and you have not
512 provided this capability (a typo, or wrong visibility, or you
513 just plain forgot, etc).
515 <P>More information, including how to optionally enable/disable the
517 <A HREF="../19_diagnostics/howto.html#3">here</A>.
522 <H2><A NAME="4_5">4.5 Aw, that's easy to fix!</A></H2>
523 <P>If you have found a bug in the library and you think you have
524 a working fix, then send it in! The main GCC site has a page
525 on <A HREF="http://gcc.gnu.org/contribute.html">submitting
526 patches</A> that covers the procedure, but for libstdc++ you
527 should also send the patch to our mailing list in addition to
528 the GCC patches mailing list. The libstdc++
529 <A HREF="../17_intro/contribute.html">contributors' page</A>
530 also talks about how to submit patches.
532 <P>In addition to the description, the patch, and the ChangeLog
533 entry, it is a Good Thing if you can additionally create a small
534 test program to test for the presence of the bug that your
535 patch fixes. Bugs have a way of being reintroduced; if an old
536 bug creeps back in, it will be caught immediately by the
537 <A HREF="#2_4">testsuite</A> -- but only if such a test exists.
541 <H1><A NAME="5_0">5.0 Miscellaneous</A></H1>
542 <H2><A NAME="5_1">5.1 string::iterator is not char*;
543 vector<T>::iterator is not T*</A></H2>
544 <P>If you have code that depends on container<T> iterators
545 being implemented as pointer-to-T, your code is broken.
547 <P>While there are arguments for iterators to be implemented in
548 that manner, A) they aren't very good ones in the long term,
549 and B) they were never guaranteed by the Standard anyway. The
550 type-safety achieved by making iterators a real class rather
551 than a typedef for <TT>T*</TT> outweighs nearly all opposing
554 <P>Code which does assume that a vector iterator <code> i </code>
555 is a pointer can often be fixed by changing <code> i </code> in
556 certain expressions to <code> &*i </code>. Future revisions
557 of the Standard are expected to bless this usage for
558 vector<> (but not for basic_string<>).
562 <H2><A NAME="5_2">5.2 What's next after libstdc++-v3?</A></H2>
563 <P>Hopefully, not much. The goal of libstdc++-v3 is to produce
564 a fully-compliant, fully-portable Standard Library. After that,
565 we're mostly done: there won't <EM>be</EM> any more compliance
569 <LI><P>The ISO Committee will meet periodically to review Defect Reports
570 in the C++ Standard. Undoubtedly some of these will result in
571 changes to the Standard, which will be reflected in patches to
572 libstdc++. Some of that is already happening, see 4.2. Some of
573 those changes are being predicted by the library maintainers, and
574 we add code to the library based on what the current proposed
575 resolution specifies.
577 <LI><P>Performance tuning. Lots of performance tuning. This too is
578 already underway for post-3.0 releases, starting with memory
579 expansion in container classes and buffer usage in synchronized
582 <LI><P>An ABI for libstdc++ will eventually be developed, so that
583 multiple binary-incompatible copies of the library can be replaced
584 with a single backwards-compatible library, like libgcc_s.so is.
586 <LI><P>The current libstdc++ contains extensions to the Library which
587 must be explicitly requested by client code (for example, the
588 hash tables from SGI). Other extensions may be added to
589 libstdc++-v3 if they seem to be "standard" enough.
590 (For example, the "long long" type from C99.)
591 Bugfixes and rewrites (to improve or fix thread safety, for
592 instance) will of course be a continuing task.
596 HREF="http://gcc.gnu.org/ml/libstdc++/1999/msg00080.html">This
597 question</A> about the next libstdc++ prompted some brief but
599 HREF="http://gcc.gnu.org/ml/libstdc++/1999/msg00084.html">speculation</A>.
603 <H2><A NAME="5_3">5.3 What about the STL from SGI?</A></H2>
604 <P>The <A HREF="http://www.sgi.com/Technology/STL/">STL from SGI</A>,
605 version 3.3, was the most recent merge of the STL codebase. The
606 code in libstdc++ contains many fixes and changes, and it is
607 very likely that the SGI code is no longer under active
608 development. We expect that no future merges will take place.
610 <P>In particular, <TT>string</TT> is not from SGI and makes no
611 use of their "rope" class (which is included as an
612 optional extension), nor is <TT>valarray</TT> and some others.
613 Classes like <TT>vector<></TT> are, however.
615 <P>The FAQ for SGI's STL (one jump off of their main page) is
620 <H2><A NAME="5_4">5.4 Extensions and Backward Compatibility</A></H2>
621 <P>Although you can specify <TT>-I</TT> options to make the
622 preprocessor search the g++-v3/ext and /backward directories,
623 it is better to refer to files there by their path, as in:
624 <!-- Careful, the leading spaces in PRE show up directly. -->
627 #include <ext/hash_map>
629 <P>Extensions to the library have
630 <A HREF="../ext/howto.html">their own page</A>.
634 <H2><A NAME="5_5">5.5 [removed]</A></H2>
635 <P>This question has become moot and has been removed. The stub
636 is here to preserve numbering (and hence links/bookmarks).
640 <H2><A NAME="5_6">5.6 Is libstdc++-v3 thread-safe?</A></H2>
641 <P>Quick answer: no, as of 2.92 (eleventh snapshot), the
642 library is not appropriate for multithreaded access. The
643 string class is MT-safe.
645 <P>This is assuming that your idea of "multithreaded"
646 is the same as ours... The general question of multithreading
647 and libstdc++-v3 is addressed in the chapter-specific advice for
648 <A HREF="http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#3">Library
649 Introduction</A>. Threadsafe containers are covered in
651 <A HREF="http://gcc.gnu.org/onlinedocs/libstdc++/23_containers/howto.html">the
652 Received Wisdom section on containers</A>.
653 <!-- I have successfully evaded the topic; my work here is
654 done- no, wait, I have to write those other sections... -->
658 <H2><A NAME="5_7">5.7 How do I get a copy of the ISO C++ Standard?</A></H2>
659 <P>Copies of the full ISO 14882 standard are available on line via the
660 ISO mirror site for committee members. Non-members, or those who
661 have not paid for the privilege of sitting on the committee and
662 sustained their two-meeting commitment for voting rights, may get a
663 copy of the standard from their respective national standards
664 organization. In the USA, this national standards organization is
665 ANSI and their website is right <A HREF="http://www.ansi.org">here</A>.
666 (And if you've already registered with them, clicking this link will
667 take you to directly to the place where you can
668 <A HREF="http://webstore.ansi.org/ansidocstore/product.asp?sku=ISO%2FIEC+14882%2D1998">buy
669 the standard on-line</A>.
671 <P>Who is your country's member body? Visit the
672 <A HREF="http://www.iso.ch/">ISO homepage</A> and find out!
675 <!-- ####################################################### -->
678 <P CLASS="fineprint"><EM>
679 Comments and suggestions are welcome, and may be sent to
680 <A HREF="mailto:libstdc++@gcc.gnu.org">the mailing list</A>.
681 <BR> $Id: index.html,v 1.9 2001/05/30 21:55:04 pme Exp $