Integrate perlio:

[p5sagit/p5-mst-13.2.git] / INSTALL

diff --git a/INSTALL b/INSTALL
index 1d27d65..836f152 100644 (file)
--- a/INSTALL
+++ b/INSTALL
@@ -24,7 +24,7 @@ with all the defaults are:
 
 Each of these is explained in further detail below.
 
-B<NOTE>: starting from the release 5.6.0 Perl will use a version
+B<NOTE>: starting from the release 5.6.0, Perl will use a version
 scheme where even-numbered subreleases (like 5.6) are stable
 maintenance releases and odd-numbered subreleases (like 5.7) are
 unstable development releases.  Development releases should not be
@@ -806,18 +806,23 @@ and the long double support.
 
 =head2 Selecting File IO mechanisms
 
-Previous versions of perl used the standard IO mechanisms as defined in
-stdio.h.  Versions 5.003_02 and later of perl allowed alternate IO
-mechanisms via a "PerlIO" abstraction, but the stdio mechanism is still
-the default and is the only supported mechanism.
+Executive summary: in Perl 5.8, you should use the default "PerlIO"
+as the IO mechanism unless you have a good reason not to.
 
-Starting from Perl 5.8 the default mechanism is to use the PerlIO
+In more detail: previous versions of perl used the standard IO
+mechanisms as defined in stdio.h.  Versions 5.003_02 and later of perl
+introduced alternate IO mechanisms via a "PerlIO" abstraction, but up
+until and including Perl 5.6, the stdio mechanism was still the default
+and the only supported mechanism.
+
+Starting from Perl 5.8, the default mechanism is to use the PerlIO
 abstraction, because it allows better control of I/O mechanisms,
 instead of having to work with (often, work around) vendors' I/O
 implementations.
 
-This PerlIO abstraction can be disabled either on the Configure
-command line with
+This PerlIO abstraction can be (but again, unless you know what you
+are doing, should not be) disabled either on the Configure command
+line with
 
        sh Configure -Uuseperlio
 
@@ -2096,6 +2101,9 @@ approach.
 
 =head1 Coexistence with earlier versions of perl5
 
+Perl 5.8 is not binary compatible with earlier versions of Perl.
+In other words, you have to recompile your XS modules.
+
 In general, you can usually safely upgrade from one version of Perl (e.g.
 5.004_04) to another similar version (e.g. 5.004_05) without re-compiling
 all of your add-on extensions.  You can also safely leave the old version