Add clarifications.

1 files changed, 22 insertions, 1 deletions

diff --git a/FAQ.in b/FAQ.in
index 1bb7bb2a27..75992effd7 100644
--- a/FAQ.in
+++ b/FAQ.in
@@ -85,6 +85,10 @@ system's tools.
 Always get the newest release of GNU binutils available.  Older releases are
 known to have bugs that prevent a successful compilation.
 
+{AJ} Please don't use binutils 2.7.  That release contains some bugs which
+might make it necessary that you've got to recompile all your glibc2
+binaries when upgrading the GNU C library.
+
 {ZW} As of release 2.1 a linker supporting symbol versions is required.  For
 Linux, get binutils-2.8.1.0.23 or later.  Other systems may have native
 linker support, but it's moot right now, because glibc has not been ported
@@ -300,6 +304,23 @@ There are some failures which are not directly related to the GNU libc:
   the test cases in the math subdirectory will fail.  The current Linux 2.1
   development kernels have fixes for the floating point support on Alpha.
 
+??	What is symbol versioning good for?  Do I need it?
+
+{AJ} Symbol versioning solves problems that are related to interface
+changes.  One version of an interface might have been introduced in a
+previous version of the GNU C library but the interface or the semantics of
+the function has been changed in the meantime.  For binary compatibility
+with the old library, a newer library needs to still have the old interface
+for old programs.  On the other hand new programs should use the new
+interface.  Symbol versioning is the solution for this problem.  The GNU
+libc version 2.1 uses by default symbol versioning if the binutils support
+it.
+
+We don't advise to build without symbol versioning since you lose binary
+compatibility if you do - for ever!  The binary compatibility you lose is
+not only against the previous version of the GNU libc (version 2.0) but also
+against future versions.
+
 
 ? Installation and configuration issues
 
@@ -600,7 +621,7 @@ file is usually the culprit.
 
 {AJ} If you have an entry "db" in /etc/nsswitch.conf you should also create
 the database files.  The glibc sources contain a Makefile which does the
-neccessary conversion and calls to create those files.  The file is
+necessary conversion and calls to create those files.  The file is
 `db-Makefile' in the subdirectory `nss' and you can call it with `make -f
 db-Makefile'.  Please note that not all services are capable of using a
 database.  Currently passwd, group, ethers, protocol, rpc, services shadow