Behaviour (make viacode 0xFFFE to return BYTE ORDER MARK,

make viacode no-allocatedcode to return the 0xFFFD) tweaks,
respective test	and doc tweaks.

p4raw-id: //depot/perl@15637

2 files changed, 14 insertions, 8 deletions

diff --git a/lib/charnames.pm b/lib/charnames.pm
index 2217f6fa2a..80f31e7eba 100644
--- a/lib/charnames.pm
+++ b/lib/charnames.pm
@@ -208,8 +208,11 @@ sub viacode
 
     if ($txt =~ m/^$hex\t\t(.+)/m) {
         return $viacode{$hex} = $1;
+    } elsif ($hex eq 'FFFE') {
+        return $viacode{$hex} = "BYTE ORDER MARK";
     } else {
-        return;
+	carp "Unknown charcode '$hex'";
+        return "\x{FFFD}";
     }
 }
 
@@ -254,8 +257,8 @@ charnames - define character names for C<\N{named}> string literal escapes.
   use charnames qw(cyrillic greek);
   print "\N{sigma} is Greek sigma, and \N{be} is Cyrillic b.\n";
 
-  print charname::viacode(0x1234); # prints "ETHIOPIC SYLLABLE SEE"
-  printf "%04X", charname::vianame("GOTHIC LETTER AHSA"); # prints "10330"
+  print charnames::viacode(0x1234); # prints "ETHIOPIC SYLLABLE SEE"
+  printf "%04X", charnames::vianame("GOTHIC LETTER AHSA"); # prints "10330"
 
 =head1 DESCRIPTION
 
@@ -397,9 +400,8 @@ will also give a warning about being deprecated.
 
 =head1 ILLEGAL CHARACTERS
 
-If you ask for a character that is illegal (like the byte order mark
-U+FFFE, or the U+FFFF) does not exist, a warning is given and the
-special Unicode I<replacement character> "\x{FFFD}" is returned.
+If you ask for a character that does not exist, a warning is given
+and the Unicode I<replacement character> "\x{FFFD}" is returned.
 
 =head1 BUGS
 
diff --git a/lib/charnames.t b/lib/charnames.t
index 7b7ad90640..42c2205713 100644
--- a/lib/charnames.t
+++ b/lib/charnames.t
@@ -12,7 +12,7 @@ BEGIN {
 
 $| = 1;
 
-print "1..37\n";
+print "1..38\n";
 
 use charnames ':full';
 
@@ -137,7 +137,8 @@ sub to_bytes {
     print "not " unless charnames::viacode(0x1234) eq "ETHIOPIC SYLLABLE SEE";
     print "ok 17\n";
 
-    print "not " if defined charnames::viacode(0x0590); # unused Hebrew
+    # Unused Hebrew.
+    print "not " unless charnames::viacode(0x0590) eq chr(0xFFFD);
     print "ok 18\n";
 }
 
@@ -216,3 +217,6 @@ print "ok 33\n";
     print "ok 37\n";
 }
 
+print "not " unless charnames::viacode(0xFFFE) eq "BYTE ORDER MARK";
+print "ok 38\n";
+