bytes(3pm) Perl Programmers Reference Guide bytes(3pm)
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, "
"; # "Length is 1"
printf "Contents are %vd
", $x; # "Contents are 400"
{
use bytes;
print "Length is ", length $x, "
"; # "Length is 2"
printf "Contents are %vd
", $x; # "Contents are 198.144"
}
For more on the implications and differences between character semantics and byte semantics, see perlunicode.
SEE ALSO
perlunicode, utf8
perl v5.8.0 2002-06-01 bytes(3pm)