$ascii = "\xa0\x{a0}";
$unicode = "\x{100}\xa0\x{a0}";

print "Latin-1 \\s : ",  $ascii =~  /\s/ ? "yes":"no","\n";
print "Latin-1 \\p{Space}: ",  $ascii =~  /\p{Space}/ ? "yes":"no","\n\n";


print "Unicode \\s: ",$unicode =~ /\s/ ? "yes":"no","\n";
print "Unicode \\p{Space}: ",$unicode =~ /\s/ ? "yes":"no","\n";