[ID 19991112.002] patch: Exporter.pm not reporting path

[p5sagit/p5-mst-13.2.git] / lib / integer.pm

diff --git a/lib/integer.pm b/lib/integer.pm
index 74039bb..f6be58a 100644 (file)
--- a/lib/integer.pm
+++ b/lib/integer.pm
@@ -1,5 +1,48 @@
 package integer;
 
+=head1 NAME
+
+integer - Perl pragma to compute arithmetic in integer instead of double
+
+=head1 SYNOPSIS
+
+    use integer;
+    $x = 10/3;
+    # $x is now 3, not 3.33333333333333333
+
+=head1 DESCRIPTION
+
+This tells the compiler to use integer operations
+from here to the end of the enclosing BLOCK.  On many machines, 
+this doesn't matter a great deal for most computations, but on those 
+without floating point hardware, it can make a big difference.
+
+Note that this affects the operations, not the numbers.  If you run this
+code
+
+    use integer;
+    $x = 1.5;
+    $y = $x + 1;
+    $z = -1.5;
+
+you'll be left with C<$x == 1.5>, C<$y == 2> and C<$z == -1>.  The $z
+case happens because unary C<-> counts as an operation.
+
+Native integer arithmetic (as provided by your C compiler) is used.
+This means that Perl's own semantics for arithmetic operations may
+not be preserved.  One common source of trouble is the modulus of
+negative numbers, which Perl does one way, but your hardware may do
+another.
+
+  % perl -le 'print (4 % -3)'
+  -2
+  % perl -Minteger -le 'print (4 % -3)'
+  1
+
+See L<perlmod/Pragmatic Modules>.
+
+=cut
+
 sub import {
     $^H |= 1;
 }