$ perl -wE 'say "p" =~ /\C0/ ? "Y" : "N"'
\C no longer supported in regex; marked by <-- HERE in m/\ <-- HERE C0/ at -e line 1.

$ perl -wE 'say "\C0"'
Unrecognized escape \C passed through at -e line 1.
C0

##</code><code>##

$ perl -wE 'say "\c0"'
"\c0" is more clearly written simply as "p" at -e line 1.
p

$ perl -wE 'say "p" =~ /\c0/ ? "Y" : "N"'
"\c0" is more clearly written simply as "p" in regex; marked by <-- HERE in m/\c0 <-- HERE / at -e line 1.
Y