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authorGurusamy Sarathy <gsar@cpan.org>1999-05-08 16:56:02 +0000
committerGurusamy Sarathy <gsar@cpan.org>1999-05-08 16:56:02 +0000
commit3160c39162b19f4390e9806b11fb472bc602a6bd (patch)
treeee6626a62cc7f199d9a87d24d87c7564033ceb8a /pod
parente16b8f4913aae827d19b2f53293805a3a74f33c6 (diff)
downloadperl-3160c39162b19f4390e9806b11fb472bc602a6bd.tar.gz
mention unpack('pP',...) footshot (from Albert Dvornik <bert@genscan.com>)
p4raw-id: //depot/perl@3333
Diffstat (limited to 'pod')
-rw-r--r--pod/perlfunc.pod5
1 files changed, 5 insertions, 0 deletions
diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index b2231a3a87..a65e3e3e46 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -4613,6 +4613,11 @@ The following efficiently counts the number of set bits in a bit vector:
$setbits = unpack("%32b*", $selectmask);
+The C<"p"> and C<"P"> formats should be used with care. Since Perl
+has no way of checking whether the value passed to C<unpack()>
+corresponds to a valid memory location, passing a pointer value that's
+not known to be valid is likely to have disastrous consequences.
+
See L</pack> for more examples.
=item untie VARIABLE