diff --git a/dcalc/CcsCeffDelayCalc.cc b/dcalc/CcsCeffDelayCalc.cc
index fbd331a4..cab8e115 100644
--- a/dcalc/CcsCeffDelayCalc.cc
+++ b/dcalc/CcsCeffDelayCalc.cc
@@ -314,7 +314,7 @@ CcsCeffDelayCalc::makeResult(const LibertyLibrary *drvr_library,
   dcalc_result.setGateDelay(gate_delay);
   dcalc_result.setDrvrSlew(drvr_slew);
 
-  for (const auto [load_pin, load_idx] : load_pin_index_map) {
+  for (const auto &[load_pin, load_idx] : load_pin_index_map) {
     ArcDelay wire_delay;
     Slew load_slew;
     loadDelaySlew(load_pin, drvr_library, rf, drvr_slew, wire_delay, load_slew);
@@ -452,9 +452,9 @@ CcsCeffDelayCalc::findVlTime(double v,
   double t_init = region_ramp_times_[0];
   double t_final = region_ramp_times_[region_count_];
   bool root_fail = false;
-  double time = findRoot([=] (double t,
-                             double &y,
-                             double &dy) {
+  double time = findRoot([&] (double t,
+                              double &y,
+                              double &dy) {
     vl(t, elmore, y, dy);
     y -= v;
   }, t_init, t_final + elmore * 3.0, .001, 20, root_fail);
diff --git a/dcalc/DmpCeff.cc b/dcalc/DmpCeff.cc
index c75b4990..c00f85aa 100644
--- a/dcalc/DmpCeff.cc
+++ b/dcalc/DmpCeff.cc
@@ -343,7 +343,7 @@ DmpAlg::findDriverParams(double ceff)
   x_[DmpParam::dt] = dt;
   x_[DmpParam::t0] = t0;
   newtonRaphson(100, x_, nr_order_, driver_param_tol,
-                [=] () { evalDmpEqns(); },
+                [this] () { evalDmpEqns(); },
 		fvec_, fjac_, index_, p_, scale_);
   t0_ = x_[DmpParam::t0];
   dt_ = x_[DmpParam::dt];
@@ -494,7 +494,7 @@ DmpAlg::findVoCrossing(double vth,
                        double t_lower,
                        double t_upper)
 {
-  FindRootFunc vo_func = [=] (double t,
+  FindRootFunc vo_func = [&] (double t,
                               double &y,
                               double &dy) {
     double vo, vo_dt;
@@ -612,7 +612,7 @@ DmpAlg::findVlCrossing(double vth,
                        double t_lower,
                        double t_upper)
 {
-  FindRootFunc vl_func = [=] (double t,
+  FindRootFunc vl_func = [&] (double t,
                               double &y,
                               double &dy) {
     double vl, vl_dt;
diff --git a/dcalc/ParallelDelayCalc.cc b/dcalc/ParallelDelayCalc.cc
index 2648797c..a27f65b9 100644
--- a/dcalc/ParallelDelayCalc.cc
+++ b/dcalc/ParallelDelayCalc.cc
@@ -86,7 +86,7 @@ ParallelDelayCalc::gateDelaysParallel(ArcDcalcArgSeq &dcalc_args,
       slew_sum += 1.0 / drvr_slew;
 
     dcalc_result.setLoadCount(load_pin_index_map.size());
-    for (const auto [load_pin, load_idx] : load_pin_index_map) {
+    for (const auto &[load_pin, load_idx] : load_pin_index_map) {
       dcalc_result.setWireDelay(load_idx, gate_result.wireDelay(load_idx));
       dcalc_result.setLoadSlew(load_idx, gate_result.loadSlew(load_idx));
     }
diff --git a/include/sta/ConcreteLibrary.hh b/include/sta/ConcreteLibrary.hh
index bacd91a0..7cf72ee6 100644
--- a/include/sta/ConcreteLibrary.hh
+++ b/include/sta/ConcreteLibrary.hh
@@ -38,7 +38,7 @@ class LibertyCell;
 class LibertyPort;
 
 typedef Map<const char*, ConcreteCell*, CharPtrLess> ConcreteCellMap;
-typedef Map<string, string> AttributeMap;
+typedef std::map<string, string> AttributeMap;
 typedef Vector<ConcretePort*> ConcretePortSeq;
 typedef Map<const char*, ConcretePort*, CharPtrLess> ConcretePortMap;
 typedef ConcreteCellMap::ConstIterator ConcreteLibraryCellIterator;
diff --git a/include/sta/ConcreteNetwork.hh b/include/sta/ConcreteNetwork.hh
index 7c62a4f7..69b7d188 100644
--- a/include/sta/ConcreteNetwork.hh
+++ b/include/sta/ConcreteNetwork.hh
@@ -38,7 +38,7 @@ class ConcreteBindingTbl;
 class ConcreteLibertyLibraryIterator;
 
 typedef Vector<ConcreteLibrary*> ConcreteLibrarySeq;
-typedef Map<string, string> AttributeMap;
+typedef std::map<string, string> AttributeMap;
 typedef Map<const char*, ConcreteLibrary*, CharPtrLess> ConcreteLibraryMap;
 typedef ConcreteLibrarySeq::ConstIterator ConcreteLibraryIterator;
 typedef Map<const char *, ConcreteInstance*,
diff --git a/include/sta/Units.hh b/include/sta/Units.hh
index c9e5baa6..541a8162 100644
--- a/include/sta/Units.hh
+++ b/include/sta/Units.hh
@@ -16,13 +16,16 @@
 
 #pragma once
 
+#include <string>
+
 namespace sta {
 
+using std::string;
+
 class Unit
 {
 public:
   Unit(const char *suffix);
-  ~Unit();
   Unit(float scale,
        const char *suffix,
        int digits);
@@ -34,9 +37,9 @@ public:
   float scale() const { return scale_; }
   void setScale(float scale);
   const char *scaleAbbreviation() const;
-  const char *suffix() const { return suffix_; }
+  const char *suffix() const { return suffix_.c_str(); }
   // scale abbreviation + suffix
-  const char *scaledSuffix() const { return scaled_suffix_; }
+  const char *scaledSuffix() const { return scaled_suffix_.c_str(); }
   void setSuffix(const char *suffix);
   int digits() const { return digits_; }
   void setDigits(int digits);
@@ -51,8 +54,8 @@ private:
   void setScaledSuffix();
 
   float scale_;			// multiplier from user units to internal units
-  const char *suffix_;		// print suffix
-  const char *scaled_suffix_;
+  string suffix_;		// print suffix
+  string scaled_suffix_;
   int digits_;			// print digits (after decimal pt)
 };
 
diff --git a/liberty/Units.cc b/liberty/Units.cc
index 9b24173c..4874c19b 100644
--- a/liberty/Units.cc
+++ b/liberty/Units.cc
@@ -29,8 +29,7 @@ using std::abs;
 
 Unit::Unit(const char *suffix) :
   scale_(1.0),
-  suffix_(stringCopy(suffix)),
-  scaled_suffix_(nullptr),
+  suffix_(suffix),
   digits_(3)
 {
   setScaledSuffix();
@@ -40,8 +39,7 @@ Unit::Unit(float scale,
 	   const char *suffix,
 	   int digits) :
   scale_(scale),
-  suffix_(stringCopy(suffix)),
-  scaled_suffix_(nullptr),
+  suffix_(suffix),
   digits_(digits)
 {
   setScaledSuffix();
@@ -50,24 +48,15 @@ Unit::Unit(float scale,
 void
 Unit::setScaledSuffix()
 {
-  stringDelete(scaled_suffix_);
-  scaled_suffix_ = stringPrint("%s%s", scaleAbbreviation(), suffix_);
-}
-
-Unit::~Unit()
-{
-  stringDelete(suffix_);
-  stringDelete(scaled_suffix_);
+  scaled_suffix_ = scaleAbbreviation() + suffix_;
 }
 
 void
 Unit::operator=(const Unit &unit)
 {
   scale_ = unit.scale_;
-  stringDelete(suffix_);
-  suffix_ = stringCopy(unit.suffix_);
-  stringDelete(scaled_suffix_);
-  scaled_suffix_ = stringCopy(unit.scaled_suffix_);
+  suffix_ = unit.suffix_;
+  scaled_suffix_ = unit.scaled_suffix_;
   digits_ = unit.digits_;
 }
 
@@ -116,8 +105,7 @@ Unit::scaleAbbreviation() const
 void
 Unit::setSuffix(const char *suffix)
 {
-  stringDelete(suffix_);
-  suffix_ = stringCopy(suffix);
+  suffix_ = suffix;
   setScaledSuffix();
 }
 
diff --git a/network/ConcreteLibrary.cc b/network/ConcreteLibrary.cc
index 820f9206..9cfca944 100644
--- a/network/ConcreteLibrary.cc
+++ b/network/ConcreteLibrary.cc
@@ -272,15 +272,15 @@ void
 ConcreteCell::setAttribute(const string &key,
                            const string &value)
 {
-  attribute_map_.insert(key, value);
+  attribute_map_[key] = value;
 }
 
 string
 ConcreteCell::getAttribute(const string &key) const 
 {
-  if (attribute_map_.hasKey(key)) {
-    return attribute_map_.findKey(key);
-  }
+  const auto &itr = attribute_map_.find(key);
+  if (itr != attribute_map_.end())
+    return itr->second;
   return "";
 }
 
diff --git a/network/ConcreteNetwork.cc b/network/ConcreteNetwork.cc
index c6c3cd00..456c3bca 100644
--- a/network/ConcreteNetwork.cc
+++ b/network/ConcreteNetwork.cc
@@ -1686,15 +1686,15 @@ void
 ConcreteInstance::setAttribute(const string &key,
                                const string &value)
 {
-  attribute_map_.insert(key, value);
+  attribute_map_[key] = value;
 }
 
 string
 ConcreteInstance::getAttribute(const string &key) const
 {
-  if (attribute_map_.hasKey(key)) {
-    return attribute_map_.findKey(key);
-  }
+  const auto &itr = attribute_map_.find(key);
+  if (itr != attribute_map_.end())
+    return itr->second;
   return "";
 }
 
diff --git a/search/Bfs.cc b/search/Bfs.cc
index cdb6d3a7..62d26196 100644
--- a/search/Bfs.cc
+++ b/search/Bfs.cc
@@ -193,7 +193,7 @@ BfsIterator::visitParallel(Level to_level,
             for (size_t k = 0; k < thread_count; k++) {
               // Last thread gets the left overs.
               size_t to = (k == thread_count - 1) ? vertex_count : from + chunk_size;
-              dispatch_queue_->dispatch( [=](int) {
+              dispatch_queue_->dispatch( [&](int) {
                 for (size_t i = from; i < to; i++) {
                   Vertex *vertex = level_vertices[i];
                   if (vertex) {