1package bytes; 2 3our $VERSION = '1.00'; 4 5$bytes::hint_bits = 0x00000008; 6 7sub import { 8 $^H |= $bytes::hint_bits; 9} 10 11sub unimport { 12 $^H &= ~$bytes::hint_bits; 13} 14 15sub AUTOLOAD { 16 require "bytes_heavy.pl"; 17 goto &$AUTOLOAD; 18} 19 20sub length ($); 21 221; 23__END__ 24 25=head1 NAME 26 27bytes - Perl pragma to force byte semantics rather than character semantics 28 29=head1 SYNOPSIS 30 31 use bytes; 32 no bytes; 33 34=head1 DESCRIPTION 35 36The C<use bytes> pragma disables character semantics for the rest of the 37lexical scope in which it appears. C<no bytes> can be used to reverse 38the effect of C<use bytes> within the current lexical scope. 39 40Perl normally assumes character semantics in the presence of character 41data (i.e. data that has come from a source that has been marked as 42being of a particular character encoding). When C<use bytes> is in 43effect, the encoding is temporarily ignored, and each string is treated 44as a series of bytes. 45 46As an example, when Perl sees C<$x = chr(400)>, it encodes the character 47in UTF-8 and stores it in $x. Then it is marked as character data, so, 48for instance, C<length $x> returns C<1>. However, in the scope of the 49C<bytes> pragma, $x is treated as a series of bytes - the bytes that make 50up the UTF8 encoding - and C<length $x> returns C<2>: 51 52 $x = chr(400); 53 print "Length is ", length $x, "\n"; # "Length is 1" 54 printf "Contents are %vd\n", $x; # "Contents are 400" 55 { 56 use bytes; 57 print "Length is ", length $x, "\n"; # "Length is 2" 58 printf "Contents are %vd\n", $x; # "Contents are 198.144" 59 } 60 61For more on the implications and differences between character 62semantics and byte semantics, see L<perlunicode>. 63 64=head1 SEE ALSO 65 66L<perlunicode>, L<utf8> 67 68=cut 69