-To compile Perl to use the old Perl 5.005 threads model, run Configure
-with the -Dusethreads -Duse5005threads options as described in INSTALL.
-This will probably only work in Tru64 4.0 and newer releases, older
-operating releases like 3.2 aren't probably going to work properly
-with threads.
-
-Beware: the Perl 5.005 threads model is known to have bugs, for
-example the regular expressions are not thread-safe. The bugs are
-very hard to fix are and therefore the 5.005 threads model is still
-classified as an experimental feature.
+If you want to use threads, you should primarily use the Perl
+5.8.0 threads model by running Configure with -Duseithreads.
+
+Perl threading is going to work only in Tru64 4.0 and newer releases,
+older operating releases like 3.2 aren't probably going to work
+properly with threads.
+
+In Tru64 V5 (at least V5.1A, V5.1B) you cannot build threaded Perl with gcc
+because the system header <pthread.h> explicitly checks for supported
+C compilers, gcc (at least 3.2.2) not being one of them. But the
+system C compiler should work just fine.
+
+=head2 Long Doubles on Tru64
+
+You cannot Configure Perl to use long doubles unless you have at least
+Tru64 V5.0, the long double support simply wasn't functional enough
+before that. Perl's Configure will override attempts to use the long
+doubles (you can notice this by Configure finding out that the modfl()
+function does not work as it should).
+
+At the time of this writing (June 2002), there is a known bug in the
+Tru64 libc printing of long doubles when not using "e" notation.
+The values are correct and usable, but you only get a limited number
+of digits displayed unless you force the issue by using C<printf
+"%.33e",$num> or the like. For Tru64 versions V5.0A through V5.1A, a
+patch is expected sometime after perl 5.8.0 is released. If your libc
+has not yet been patched, you'll get a warning from Configure when
+selecting long doubles.
+
+=head2 DB_File tests failing on Tru64
+
+The DB_File tests (db-btree.t, db-hash.t, db-recno.t) may fail you
+have installed a newer version of Berkeley DB into the system and the
+-I and -L compiler and linker flags introduce version conflicts with
+the DB 1.85 headers and libraries that came with the Tru64. For example,
+mixing a DB v2 library with the DB v1 headers is a bad idea. Watch
+out for Configure options -Dlocincpth and -Dloclibpth, and check your
+/usr/local/include and /usr/local/lib since they are included by default.
+
+The second option is to explicitly instruct Configure to detect the
+newer Berkeley DB installation, by supplying the right directories with
+C<-Dlocincpth=/some/include> and C<-Dloclibpth=/some/lib> B<and> before
+running "make test" setting your LD_LIBRARY_PATH to F</some/lib>.
+
+The third option is to work around the problem by disabling the
+DB_File completely when build Perl by specifying -Ui_db to Configure,
+and then using the BerkeleyDB module from CPAN instead of DB_File.
+The BerkeleyDB works with Berkeley DB versions 2.* or greater.
+
+The Berkeley DB 4.1.25 has been tested with Tru64 V5.1A and found
+to work. The latest Berkeley DB can be found from L<http://www.sleepycat.com>.