From: Zefram <zefram@fysh.org>
Date: Mon, 30 Nov 2009 10:42:14 +0000 (+0100)
Subject: Document if.pm in perlfunc
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=c362798e2bfee6dd58e97b97c7f3aa37c2c6af9f;p=p5sagit%2Fp5-mst-13.2.git

Document if.pm in perlfunc
---

diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index 540b723..188647c 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -7060,6 +7060,15 @@ block scope (like C<strict> or C<integer>, unlike ordinary modules,
 which import symbols into the current package (which are effective
 through the end of the file).
 
+Because C<use> takes effect at compile time, it doesn't respect the
+ordinary flow control of the code being compiled.  In particular, putting
+a C<use> inside the false branch of a conditional doesn't prevent it
+from being processed.  If a module or pragma needs to be loaded only
+conditionally, this can be done using the L<if> pragma:
+
+    use if $] < 5.008, "utf8";
+    use if WANT_WARNINGS, warnings => qw(all);
+
 There's a corresponding C<no> command that unimports meanings imported
 by C<use>, i.e., it calls C<unimport Module LIST> instead of C<import>.
 It behaves exactly as C<import> does with respect to VERSION, an