use RegexpCharClassesThai;  #Regexp-CharClasses-Thai.pm
...
my @inthai = &IsThaiLCons;
...
Undefined subroutine &ModPerl::ROOT::ModPerl::PerlRun::var_www_cgi_test_2d
+thai_2dmod_2epl::IsThaiLCons called at /var/www/cgi/test-thai-mod.pl line 19.