\x{263A}     [1,8]  hex char          (example shown: SMILEY)
\x{ 263A }          Same, but shows optional blanks inside and
                    adjoining the braces

##</code><code>##

  DB<55> p join ",",map {ord} split //, "\x{ 41 }"                                                                      
0                                                                                                                         
  DB<56> p join ",",map {ord} split //, "\x{41}"                                                                        
65                                                                                                                        
  DB<57> p join ",",map {ord} split //, "\x{263A}"                                                                      
9786                                                                                                                      
  DB<58> p join ",",map {ord} split //, "\x{ 263A }"                                                                    
0                                                                                                                         
  DB<59> p "\x{41}"                                                                                                     
A                                                                                                                         
  DB<60> p "\x{ 41 }"                                                                                                   
^@                                                   

##</code><code>##

  DB<65> use warnings; "\x{ 263A }"                                                                                     
Non-hex character ' ' terminates \x early.  Resolved as "\x{00}" at (eval            

##</code><code>##

C:\tmp>%PERL% -w
print $];
print "\x{ 41 }";
Illegal hexadecimal digit ' ' ignored at - line 2.
__END__
5.024001

##</code><code>##

C:\tmp>%PERL_532% -w
print $];
print "\x{ 41 }";
Non-hex character ' ' terminates \x early.  Resolved as "\x{00}" at - line 2.
__END__
5.032001