update

From-SVN: r17110

gcc/cp/g++FAQ.texi

@@ -3,7 +3,7 @@
 @setfilename g++FAQ.info
 @settitle Frequently asked questions about the GNU C++ compiler
 @setchapternewpage off
-@c version: @(#)g++FAQ.texi	1.56 09/15/97
+@c version: @(#)g++FAQ.texi	1.57 12/14/97
 @c %**end of header
 
 @iftex
@@ -12,7 +12,7 @@
 @titlepage
 @title G++ FAQ
 @subtitle Frequently asked questions about the GNU C++ compiler
-@subtitle September 14, 1997
+@subtitle December 14, 1997
 @sp 1
 @author Joe Buck
 @page
@@ -35,15 +35,14 @@ all those who sent suggestions for improvements.  Thanks to Marcus Speh
 for doing the index.  A hypertext version is available on the World Wide
 Web at @file{http://www.cygnus.com/misc/g++FAQ_toc.html}.
 
-This document has just been reorganized a bit.  There is some new
-information about upcoming g++ releases and egcs; more needs to be done
-but that will need to wait for next time.  A diff would look misleadingly
-large, since I blew away and rebuilt the texinfo menus.
+@strong{News flash}: egcs has been released, and the 2.8.0 release is
+expected very soon!
 
 Please send updates and corrections to the FAQ to
 @code{jbuck@@synopsys.com}.  Please do @emph{not} use me as a resource
 to get your questions answered; that's what @file{gnu.g++.help} is for and I
-don't have the time to support the net's use of g++.
+don't have the time to support the net's use of g++.  If you ignore this
+request your message to me may be deleted without a reply.  Sorry.
 
 Many FAQs, including this one, are available on the archive site
 ``rtfm.mit.edu''; see @*
@@ -64,6 +63,7 @@ or in HTML form at @file{http://www.cerfnet.com/~mpcline/On-Line-C++-FAQs/}.
 
 @menu
 * basics::                      What is g++?  How do I get it?
+* egcs and 2.8.0::              The next generation(s) of g++
 * installation::                How to install, installation problems
 * evolution::                   The Evolution of g++
 * User Problems::               Commonly reported problems and bugs
@@ -81,6 +81,14 @@ The basics: what is g++?
 * g++ for other platforms::     
 * 1.x vs 2.x versions::         
 
+The Next Generation(s) of g++
+
+* egcs-intro::                  What is egcs?
+* egcs-whats-new::              What's new in egcs vs 2.7.2?
+* egcs-run-both::               How can I run both egcs and an FSF release?
+* egcs-vs-2.8.0::               How will egcs affect 2.8.0?
+* egcs-robustness::             How robust is egcs-1.0?
+
 Installation Issues and Problems
 
 * gcc-2 + g++-1::               
@@ -102,11 +110,8 @@ Installation Issues and Problems
 
 The Evolution of g++
 
-* version 2.7.x::               
+* version 2.7.x::               What's changed in 2.7.x from earlier versions
 * libstdc++::                   
-* new work::                    
-* egcs::                        
-* When?::                       
 
 User Problems
 
@@ -138,7 +143,7 @@ User Problems
 * assignment to streams::       
 @end menu
 
-@node basics, installation, Top, Top
+@node basics, egcs and 2.8.0, Top, Top
 @chapter The basics: what is g++?
 
 @cindex Free Software Foundation
@@ -167,6 +172,11 @@ or GPL (@pxref{legalities}).
 @node latest versions, g++ for Unix, basics, basics
 @section What is the latest version of gcc, g++, and libg++?
 
+@cindex egcs release
+
+The egcs project (on the Web: @file{http://www.cygnus.com/egcs/}) has
+now released egcs-1.0 as of December 3, 1997.
+
 @cindex gcc/g++, version date
 The current version of gcc/g++ is 2.7.2.3, released August 20, 1997.
 Although that looks very recent, the only change is a minor patch to
@@ -436,7 +446,144 @@ 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.''
 
-@node installation, evolution, basics, Top
+@node egcs and 2.8.0, installation, basics, Top
+@chapter The Next Generation(s) of g++
+
+@menu
+* egcs-intro::                  What is egcs?
+* egcs-whats-new::              What's new in egcs vs 2.7.2?
+* egcs-run-both::               How can I run both egcs and an FSF release?
+* egcs-vs-2.8.0::               How will egcs affect 2.8.0?
+* egcs-robustness::             How robust is egcs-1.0?
+@end menu
+
+@node egcs-intro, egcs-whats-new, egcs and 2.8.0, egcs and 2.8.0
+@section What is egcs?
+
+egcs is the Experimental GNU compiler system (see
+@file{http://www.cygnus.com/egcs} on the Web).  It is an effort to
+accelerate development of new gcc features by providing a more open
+development model than gcc has traditionally used.
+
+The first egcs release, egcs-1.0, came out on December 3, 1997.
+Questions not addressed here may be answered in the egcs FAQ
+(@file{http://www.cygnus.com/egcs/faq.html}).
+
+@node egcs-whats-new, egcs-run-both, egcs-intro, egcs and 2.8.0
+@section What new C++ features are in egcs?
+
+@strong{Note}: unless indicated otherwise, these features are expected
+to be present in g++ 2.8.0 when released.
+
+@itemize @bullet
+@item
+@cindex integrated libstdc++
+
+The standard C++ classes are integrated with the egcs release (this is
+@emph{not} expected to be true of gcc-2.8.0).  libg++ is not being
+supported, though a version that will work with egcs has been
+contributed (FIXME: pointer?).  The compiler and library are configured
+and built in one step.
+
+@item
+@cindex new template implementation
+A completely new template implementation, much closer to the draft
+standard.  Limitations in 2.7.2.x concerning inlining template functions
+will be eliminated.  Static template data members, template class member
+functions, partial specification, and default template arguments will be
+supported.  An instantiation method resembling that used in Borland C++
+(instantiating functions possibly in multiple .o files and using weak
+symbols to link correctly) is provided, in addition to other
+options.  The SGI version of STL is shipped verbatim with libstdc++.
+
+@item
+@cindex redundant template elimination
+@cindex templates: removing redundancy
+On ELF platforms (Linux/ELF, Solaris, SVR4), if the GNU linker is used,
+duplicated template functions and virtual function tables are eliminated
+at link time.
+
+@item
+@cindex repository
+@cindex -frepo
+The @code{-frepo} flag is supported in egcs (it will not be in 2.8.0).
+However, because of the previous item, I don't recommend its use on ELF
+systems.
+
+@item
+@cindex new exception implementation
+Exception handling has been re-worked; exceptions will work together
+with optimization.
+Actually, there are two separate implementations: one based on setjmp/longjmp
+and designed to be highly portable, and one designed to be more efficient but
+requiring more processor-specific support (getting exceptions right has proven
+to be extremely difficult and has been the chief obstacle to getting a new
+release out).
+
+@item
+@cindex RTTI
+RTTI has been re-done to work correctly and is on by default.
+
+@item
+@cindex overloading
+Overloading has been re-worked to conform to the latest draft of the
+standard.
+
+@item
+There are many more changes: see @file{http://www.cygnus.com/egcs/c++features.html} for a list.
+@end itemize
+
+Features that are still missing include namespaces and templates as
+template arguments.
+
+@node egcs-run-both, egcs-vs-2.8.0, egcs-whats-new, egcs and 2.8.0
+@section How can I run both egcs and an FSF release of g++ on the same machine?
+
+The recommended approach is to provide a different argument to the
+@code{--prefix} flag when you configure egcs.  For example, say
+@code{--prefix=/usr/local/egcs} and then, after installation, you
+can make symbolic links from @file{/usr/local/egcs/bin} to whereever
+you want, for example
+
+@example
+ln -s /usr/local/egcs/bin/gcc /usr/local/bin/egcc
+ln -s /usr/local/egcs/bin/g++ /usr/local/bin/eg++
+@end example
+
+@node egcs-vs-2.8.0, egcs-robustness, egcs-run-both, egcs and 2.8.0
+@section What about 2.8.0?  How does egcs affect the 2.8.x development?
+
+2.8.0 is expected Real Soon Now (I would guess by the end of 1997, but that
+is only a guess).  The C++ front end should be essentially the same.
+
+Bug fixes generated in egcs will be passed to the 2.8.x releases for
+inclusion; the reverse is also taking place, though a bug fix may
+appear in one before it does in the other.
+
+@node egcs-robustness,  , egcs-vs-2.8.0, egcs and 2.8.0
+@section How solid is egcs-1.0?
+
+While the 'e' stands for 'experimental', egcs has been tested thoroughly
+and should be of high quality.  There are a few glitches which should be
+fixed shortly (in a 1.0.1 release, probably in early January):
+
+@itemize @bullet
+@item
+Deeply nested templates sometimes lead to a very large memory requirement
+if the @code{-Wreturn-type} option is on (note: this flag is implicitly
+turned on by @code{-W} or @code{-Wall}.  A workaround is to give the
+flag @code{-Wno-return-type} if you use @code{-Wall}.
+
+@item
+On Red Hat 5.0, it may be necessary to link all C++ programs with
+@code{-lpthread} to work around an undefined symbol problem.
+
+@item
+A patch is needed to fix egcs on Solaris/X86.  It is in the egcs FAQ
+(see above).
+@end itemize
+
+@node installation, evolution, egcs and 2.8.0, Top
 @chapter Installation Issues and Problems
 
 @menu
@@ -554,6 +701,11 @@ debug format (e.g. Suns running SunOS 4.x), the GNU linker compresses
 the debug symbol table considerably.  The 2.7 version adds some symbol
 table compression for ELF and Solaris targets.
 
+Users of egcs or 2.8.0 (when released) on ELF systems should definitely
+use GNU ld (2.8 or later), as it will automatically remove duplicate
+instantiations of templates, virtual function tables, or ``outlined''
+copies of inline functions.
+
 @cindex collect linker, advantages
 Advantages of collect:
 
@@ -951,10 +1103,7 @@ in the future.
 
 @menu
 * version 2.7.x::               What's changed in 2.7.x from earlier versions
-* libstdc++::                   The GNU C++ standard library
-* new work::                    What's been done since 2.7.x
-* egcs::                        The Experimental GNU Compiler System
-* When?::                       When can I get all this new stuff?
+* libstdc++::                   
 @end menu
 
 @node version 2.7.x, libstdc++, evolution, evolution
@@ -1086,7 +1235,7 @@ though they are not needed).
 
 @end itemize
 
-@node libstdc++, new work, version 2.7.x, evolution
+@node libstdc++,  , version 2.7.x, evolution
 @section The GNU Standard C++ Library
 
 The GNU Standard C++ Library (also called the ``GNU ANSI C++ Library''
@@ -1112,67 +1261,6 @@ The maintainers of libg++ have de-emphasized work on the older libg++ classes
 in favor of enhancing libstdc++ to cover the full language, so while libg++
 will always be available, enhancements to it should not be expected.
 
-@node new work, egcs, libstdc++, evolution
-@section What can we expect in future gcc releases?
-
-A great deal of work has gone into enhancements to the C++ front end, as well
-as to other aspects of the compiler.
-
-The next major release(s) of gcc/g++ can be expected to have the following
-features:
-
-@itemize @bullet
-@cindex new template implementation
-@item
-A completely new template implementation, much closer to the draft
-standard.  Limitations in 2.7.2.x concerning inlining template functions
-will be eliminated.  Static template data members, template class member
-functions, partial specification, and default template arguments will be
-supported.  An instantiation method resembling that used in Borland C++
-(instantiating functions possibly in multiple .o files and using weak
-symbols to link correctly) will be provided, in addition to other
-options.  The SGI version of STL will be shipped with libstdc++ and will
-compile unchanged.
-
-@item
-@cindex new exception implementation
-Exception handling has been re-worked; exceptions will work together
-with optimization.
-Actually, there are two separate implementations: one based on setjmp/longjmp
-and designed to be highly portable, and one designed to be more efficient but
-requiring more processor-specific support (getting exceptions right has proven
-to be extremely difficult and has been the chief obstacle to getting a new
-release out).
-
-@item
-@cindex RTTI
-RTTI has been re-done to work correctly and is on by default.
-
-@item
-@cindex overloading
-Overloading has been re-worked to conform to the latest draft of the
-standard.
-@end itemize
-
-Features that are still missing include namespaces and templates as
-template arguments.
-
-@node egcs, When?, new work, evolution
-@section What's this I hear about egcs?
-
-The egcs effort is a new effort to merge several threads of gcc
-development and to provide a faster development process.
-For more information see @file{http://www.cygnus.com/egcs/}.
-
-@node When?,  , egcs, evolution
-@section OK, when can I get this stuff?
-
-The FSF has a policy of never announcing release dates in advance.
-I'm sure this is frustrating to a lot of people, since it's taken
-so long, and this frustration was one of the reasons the egcs effort
-was created.  An egcs release should be expected to occur in the
-very near future.   [ More on this next time ].
-
 @node User Problems, legalities, evolution, Top
 @chapter User Problems
 
@@ -1620,8 +1708,11 @@ another manual @file{libio/iostream.texi} describing the iostreams
 implementation.
 @item
 While there is no libg++-specific document describing the STL
-implementation, SGI's web site, at @file{http://www.sgi.com/Technology/STL/},
-is an excellent resource.
+implementation, SGI's web site, at
+@file{http://www.sgi.com/Technology/STL/}, is an excellent resource.
+Note that the SGI version of STL is the one that is included with the
+egcs and 2.8.0 (when it occurs) releases of g++.
+
 @end itemize
 
 @node templates, undefined templates, documentation, User Problems