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bytes - Perl pragma to force byte semantics rather than character semantics
The use bytes pragma disables character semantics for the rest of the lexical
scope in which it appears. no bytes can be used to reverse the effect of use
bytes within the current lexical scope.
Perl normally assumes character semantics in the presence of character data (i.e. data that
has come from a source that has been marked as being of a particular character encoding). When
use bytes is in effect, the encoding is temporarily ignored, and each string is
treated as a series of bytes.
As an example, when Perl sees $x = chr(400), it encodes the character in UTF-8
and stores it in $x. Then it is marked as character data, so, for instance, length $x
returns 1. However, in the scope of the bytes pragma, $x is treated
as a series of bytes - the bytes that make up the UTF8 encoding - and length $x
returns 2:
$x = chr(400);
print "Length is ", length $x, "\n"; # "Length is 1"
printf "Contents are %vd\n", $x; # "Contents are 400"
{
use bytes;
print "Length is ", length $x, "\n"; # "Length is 2"
printf "Contents are %vd\n", $x; # "Contents are 198.144"
}
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For more on the implications and differences between character semantics and byte
semantics, see perlunicode.
perlunicode, utf8
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