package bytes; our $VERSION = '1.03'; $bytes::hint_bits = 0x00000008; sub import { $^H |= $bytes::hint_bits; } sub unimport { $^H &= ~$bytes::hint_bits; } sub AUTOLOAD { require "bytes_heavy.pl"; goto &$AUTOLOAD if defined &$AUTOLOAD; require Carp; Carp::croak("Undefined subroutine $AUTOLOAD called"); } sub length (_); sub chr (_); sub ord (_); sub substr ($$;$$); sub index ($$;$); sub rindex ($$;$); 1; __END__ =head1 NAME bytes - Perl pragma to force byte semantics rather than character semantics =head1 SYNOPSIS use bytes; ... chr(...); # or bytes::chr ... index(...); # or bytes::index ... length(...); # or bytes::length ... ord(...); # or bytes::ord ... rindex(...); # or bytes::rindex ... substr(...); # or bytes::substr no bytes; =head1 DESCRIPTION The C pragma disables character semantics for the rest of the lexical scope in which it appears. C can be used to reverse the effect of C within the current lexical scope. Perl normally assumes character semantics in the presence of character data (i.e. data that has come from a source that has been marked as being of a particular character encoding). When C is in effect, the encoding is temporarily ignored, and each string is treated as a series of bytes. As an example, when Perl sees C<$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, C returns C<1>. However, in the scope of the C pragma, $x is treated as a series of bytes - the bytes that make up the UTF8 encoding - and C returns C<2>: $x = chr(400); print "Length is ", length $x, "\n"; # "Length is 1" printf "Contents are %vd\n", $x; # "Contents are 400" { use bytes; # or "require bytes; bytes::length()" print "Length is ", length $x, "\n"; # "Length is 2" printf "Contents are %vd\n", $x; # "Contents are 198.144" } chr(), ord(), substr(), index() and rindex() behave similarly. For more on the implications and differences between character semantics and byte semantics, see L and L. =head1 LIMITATIONS bytes::substr() does not work as an lvalue(). =head1 SEE ALSO L, L, L =cut