X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2Fbytes.pm;h=f2f7e0157cb8a92ec97e4dab2e248dc23af56781;hb=22d4bb9ccb8701e68f9243547d7e3a3c55f70908;hp=f93d6158d9fc6f177eac2335a9948ba076df7a54;hpb=4b19af017623bfa3bb72bb164598a517f586e0d3;p=p5sagit%2Fp5-mst-13.2.git diff --git a/lib/bytes.pm b/lib/bytes.pm index f93d615..f2f7e01 100644 --- a/lib/bytes.pm +++ b/lib/bytes.pm @@ -38,11 +38,28 @@ 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). - -To understand the implications and differences between character +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 UTF8 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; + print "Length is ", length $x, "\n"; # "Length is 2" + printf "Contents are %vd\n", $x; # "Contents are 198.144" + } + +For more on the implications and differences between character semantics and byte semantics, see L. =head1 SEE ALSO