strncat(dt, src) sv_catpvn(sv, s)
sprintf(s, fmt, ...) sv_setpvf(sv, fmt, ...)
-Note also the existence of C<sv_catpvf> and C<sv_catpvfn>, combining
+Note also the existence of C<sv_catpvf> and C<sv_vcatpvfn>, combining
concatenation with formatting.
=head2 Character Class Tests