diff --git a/NEWS.md b/NEWS.md
index 5497ea1..953a56a 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -16,6 +16,8 @@
 
 * Replace call to `Rf_error()` with `Rcpp::stop()`; RcppCore/Rcpp#1247
 
+* Fix UBs in the C++ glue code; #380
+
 # version 0.8-5
 
 * avoid -Wformat-security warning on CRAN
diff --git a/src/RcppExports.cpp b/src/RcppExports.cpp
index 8db11f2..71afde4 100644
--- a/src/RcppExports.cpp
+++ b/src/RcppExports.cpp
@@ -40,28 +40,28 @@ BEGIN_RCPP
 END_RCPP
 }
 // ud_compare
-IntegerVector ud_compare(NumericVector x, NumericVector y, CharacterVector xn, CharacterVector yn);
+IntegerVector ud_compare(NumericVector x, NumericVector y, std::string xn, std::string yn);
 RcppExport SEXP _units_ud_compare(SEXP xSEXP, SEXP ySEXP, SEXP xnSEXP, SEXP ynSEXP) {
 BEGIN_RCPP
     Rcpp::RObject rcpp_result_gen;
     Rcpp::RNGScope rcpp_rngScope_gen;
     Rcpp::traits::input_parameter< NumericVector >::type x(xSEXP);
     Rcpp::traits::input_parameter< NumericVector >::type y(ySEXP);
-    Rcpp::traits::input_parameter< CharacterVector >::type xn(xnSEXP);
-    Rcpp::traits::input_parameter< CharacterVector >::type yn(ynSEXP);
+    Rcpp::traits::input_parameter< std::string >::type xn(xnSEXP);
+    Rcpp::traits::input_parameter< std::string >::type yn(ynSEXP);
     rcpp_result_gen = Rcpp::wrap(ud_compare(x, y, xn, yn));
     return rcpp_result_gen;
 END_RCPP
 }
 // ud_convert
-NumericVector ud_convert(NumericVector val, CharacterVector from, CharacterVector to);
+NumericVector ud_convert(NumericVector val, std::string from, std::string to);
 RcppExport SEXP _units_ud_convert(SEXP valSEXP, SEXP fromSEXP, SEXP toSEXP) {
 BEGIN_RCPP
     Rcpp::RObject rcpp_result_gen;
     Rcpp::RNGScope rcpp_rngScope_gen;
     Rcpp::traits::input_parameter< NumericVector >::type val(valSEXP);
-    Rcpp::traits::input_parameter< CharacterVector >::type from(fromSEXP);
-    Rcpp::traits::input_parameter< CharacterVector >::type to(toSEXP);
+    Rcpp::traits::input_parameter< std::string >::type from(fromSEXP);
+    Rcpp::traits::input_parameter< std::string >::type to(toSEXP);
     rcpp_result_gen = Rcpp::wrap(ud_convert(val, from, to));
     return rcpp_result_gen;
 END_RCPP
@@ -232,48 +232,48 @@ BEGIN_RCPP
 END_RCPP
 }
 // R_ut_raise
-SEXP R_ut_raise(SEXP a, IntegerVector i);
+SEXP R_ut_raise(SEXP a, int i);
 RcppExport SEXP _units_R_ut_raise(SEXP aSEXP, SEXP iSEXP) {
 BEGIN_RCPP
     Rcpp::RObject rcpp_result_gen;
     Rcpp::RNGScope rcpp_rngScope_gen;
     Rcpp::traits::input_parameter< SEXP >::type a(aSEXP);
-    Rcpp::traits::input_parameter< IntegerVector >::type i(iSEXP);
+    Rcpp::traits::input_parameter< int >::type i(iSEXP);
     rcpp_result_gen = Rcpp::wrap(R_ut_raise(a, i));
     return rcpp_result_gen;
 END_RCPP
 }
 // R_ut_root
-SEXP R_ut_root(SEXP a, IntegerVector i);
+SEXP R_ut_root(SEXP a, int i);
 RcppExport SEXP _units_R_ut_root(SEXP aSEXP, SEXP iSEXP) {
 BEGIN_RCPP
     Rcpp::RObject rcpp_result_gen;
     Rcpp::RNGScope rcpp_rngScope_gen;
     Rcpp::traits::input_parameter< SEXP >::type a(aSEXP);
-    Rcpp::traits::input_parameter< IntegerVector >::type i(iSEXP);
+    Rcpp::traits::input_parameter< int >::type i(iSEXP);
     rcpp_result_gen = Rcpp::wrap(R_ut_root(a, i));
     return rcpp_result_gen;
 END_RCPP
 }
 // R_ut_log
-SEXP R_ut_log(SEXP a, NumericVector base);
+SEXP R_ut_log(SEXP a, double base);
 RcppExport SEXP _units_R_ut_log(SEXP aSEXP, SEXP baseSEXP) {
 BEGIN_RCPP
     Rcpp::RObject rcpp_result_gen;
     Rcpp::RNGScope rcpp_rngScope_gen;
     Rcpp::traits::input_parameter< SEXP >::type a(aSEXP);
-    Rcpp::traits::input_parameter< NumericVector >::type base(baseSEXP);
+    Rcpp::traits::input_parameter< double >::type base(baseSEXP);
     rcpp_result_gen = Rcpp::wrap(R_ut_log(a, base));
     return rcpp_result_gen;
 END_RCPP
 }
 // R_ut_parse
-SEXP R_ut_parse(CharacterVector name);
+SEXP R_ut_parse(std::string name);
 RcppExport SEXP _units_R_ut_parse(SEXP nameSEXP) {
 BEGIN_RCPP
     Rcpp::RObject rcpp_result_gen;
     Rcpp::RNGScope rcpp_rngScope_gen;
-    Rcpp::traits::input_parameter< CharacterVector >::type name(nameSEXP);
+    Rcpp::traits::input_parameter< std::string >::type name(nameSEXP);
     rcpp_result_gen = Rcpp::wrap(R_ut_parse(name));
     return rcpp_result_gen;
 END_RCPP
diff --git a/src/udunits.cpp b/src/udunits.cpp
index 11260ab..9036868 100644
--- a/src/udunits.cpp
+++ b/src/udunits.cpp
@@ -80,7 +80,7 @@ void ud_set_encoding(std::string enc_str) {
 
 // [[Rcpp::export]]
 IntegerVector ud_compare(NumericVector x, NumericVector y,
-                         CharacterVector xn, CharacterVector yn)
+                         std::string xn, std::string yn)
 {
   bool swapped = false;
 
@@ -91,11 +91,12 @@ IntegerVector ud_compare(NumericVector x, NumericVector y,
   }
 
   IntegerVector out(x.size());
+  if (y.size() == 0) return IntegerVector(0);
   for (std::string &attr : x.attributeNames())
     out.attr(attr) = x.attr(attr);
 
-  ut_unit *ux = ut_parse(sys, ut_trim(xn[0], enc), enc);
-  ut_unit *uy = ut_parse(sys, ut_trim(yn[0], enc), enc);
+  ut_unit *ux = ut_parse(sys, ut_trim(xn.data(), enc), enc);
+  ut_unit *uy = ut_parse(sys, ut_trim(yn.data(), enc), enc);
 
   if (ut_compare(ux, uy) != 0) {
     NumericVector y_cv = clone(y);
@@ -127,9 +128,11 @@ IntegerVector ud_compare(NumericVector x, NumericVector y,
 }
 
 // [[Rcpp::export]]
-NumericVector ud_convert(NumericVector val, CharacterVector from, CharacterVector to) {
-  ut_unit *u_from = ut_parse(sys, ut_trim(from[0], enc), enc);
-  ut_unit *u_to = ut_parse(sys, ut_trim(to[0], enc), enc);
+NumericVector ud_convert(NumericVector val, std::string from, std::string to) {
+  if (val.size() == 0) return val;
+
+  ut_unit *u_from = ut_parse(sys, ut_trim(from.data(), enc), enc);
+  ut_unit *u_to = ut_parse(sys, ut_trim(to.data(), enc), enc);
 
   cv_converter *cv = ut_get_converter(u_from, u_to);
   cv_convert_doubles(cv, &(val[0]), val.size(), &(val[0]));
@@ -256,35 +259,27 @@ SEXP R_ut_divide(SEXP numer, SEXP denom) {
 }
 
 // [[Rcpp::export]]
-SEXP R_ut_raise(SEXP a, IntegerVector i) {
-  if (i.length() != 1)
-    stop("i should have length 1");
-  return ut_wrap(ut_raise(ut_unwrap(a), i[0]));
+SEXP R_ut_raise(SEXP a, int i) {
+  return ut_wrap(ut_raise(ut_unwrap(a), i));
 }
 
 // [[Rcpp::export]]
-SEXP R_ut_root(SEXP a, IntegerVector i) {
-  if (i.length() != 1)
-    stop("i should have length 1");
-  return ut_wrap(ut_root(ut_unwrap(a), i[0]));
+SEXP R_ut_root(SEXP a, int i) {
+  return ut_wrap(ut_root(ut_unwrap(a), i));
 }
 
 // # nocov end
 
 // [[Rcpp::export]]
-SEXP R_ut_log(SEXP a, NumericVector base) {
-  if (base.length() != 1)
-    stop("base should have length 1");
-  if (base[0] <= 0)
-    stop("base should be positive");
-  return ut_wrap(ut_log(base[0], ut_unwrap(a)));
+SEXP R_ut_log(SEXP a, double base) {
+  return ut_wrap(ut_log(base, ut_unwrap(a)));
 }
 
 // [[Rcpp::export]]
-SEXP R_ut_parse(CharacterVector name) {
-  ut_unit *u = ut_parse(sys, ut_trim(name[0], enc), enc);
+SEXP R_ut_parse(std::string name) {
+  ut_unit *u = ut_parse(sys, ut_trim(name.data(), enc), enc);
   if (u == NULL)
-    stop("syntax error, cannot parse '%s'", (char*)name[0]);
+    stop("syntax error, cannot parse '%s'", name);
   return ut_wrap(u);
 }