perldelta for 2f465e08e / #123652

[perl5.git] / pod / perldata.pod

diff --git a/pod/perldata.pod b/pod/perldata.pod
index d5df9e3..5316fe2 100644 (file)
--- a/pod/perldata.pod
+++ b/pod/perldata.pod
@@ -531,53 +531,6 @@ Perl 5.8.0, but that caused more confusion and breakage than good.
 Multi-number v-strings like C<v65.66> and C<65.66.67> continue to
 be v-strings always.
 
-=head3 Special floating point
-
-Floating point values include the special values C<Inf> and C<NaN>,
-for infinity and not-a-number.  The infinity can be also negative.
-
-The infinity is the result of certain math operations that overflow
-the floating point range, like 9**9**9.  The not-a-number is the
-result when the result is undefined or unrepresentable.  Though note
-that you cannot get C<NaN> from some common "undefined" or
-"out-of-range" operations like dividing by zero, or square root of
-a negative number, since Perl generates fatal errors for those.
-
-The infinity and not-a-number have their own special arithmetic rules.
-The general rule is that they are "contagious": C<Inf> plus one is
-C<Inf>, and C<NaN> plus one is C<NaN>.  Where things get interesting
-is when you combine infinities and not-a-numbers: C<Inf> minus C<Inf>
-and C<Inf> divided by C<INf> are C<NaN> (while C<Inf> plus C<Inf> is
-C<Inf> and C<Inf> times C<Inf> is C<Inf>).
-
-Perl doesn't understand C<Inf> and C<NaN> as numeric literals, but you
-can have them as strings, and Perl will convert them as needed: "Inf" + 1.
-(If you want to have them as kind of literals, you can import them from
-the POSIX extension.)
-
-Note that on input (string to number) Perl accepts C<Inf> and C<NaN>
-in many forms.   Case is ignored, and the Win32-specific forms like
-C<1.#INF> are understood, but on output the values are normalized to
-C<Inf> and C<NaN>.
-
-The C<NaN> has two special features of its own. Firstly, it comes in
-two flavors, quiet and signaling.  What this means is depends on the
-platform.  Secondly, it may have "payload" of a number of bits.  The
-number of bits available again depends on the platform.  (Though for
-the most common floating point format, 64-bit IEEE 754, there is
-room for 51 bits.)
-
-The payload is propagated on straight copies, but on operations
-(like addition) the result (which payload bits end up where) again
-depends on the platform.  You can generate a NaN with payload by
-e.g. "nan(0x123)".
-
-The default stringification of not-a-numbers will just show the C<NaN>
-but you can use C<printf %#g> to see the payload: the C<#> is the key.
-The payload will be shown as hexadecimal integer if possible on
-the platform (floating point values may have more bits than integers),
-if not, as a string of hexadecimal bytes.
-
 =head3 Special Literals
 X<special literal> X<__END__> X<__DATA__> X<END> X<DATA>
 X<end> X<data> X<^D> X<^Z>