bytes(3)

NAME

bytes - Perl pragma to force byte semantics rather than
character semantics

SYNOPSIS

use bytes;
no bytes;

DESCRIPTION

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, "0; # "Length is 1"
printf "Contents are %vd0, $x; # "Contents are

400"
{

use bytes;
print "Length is ", length $x, "0; # "Length is 2"
printf "Contents are %vd0, $x; # "Contents are

198.144"

}

For more on the implications and differences between char
acter semantics and byte semantics, see perlunicode.

SEE ALSO

perlunicode, utf8

perl v5.8.0 2002-06-01 bytes(3)