diff --git a/externals/coda-oss/modules/c++/cli/source/ArgumentParser.cpp b/externals/coda-oss/modules/c++/cli/source/ArgumentParser.cpp
index 367ff9edce..e6c8fb4442 100644
--- a/externals/coda-oss/modules/c++/cli/source/ArgumentParser.cpp
+++ b/externals/coda-oss/modules/c++/cli/source/ArgumentParser.cpp
@@ -579,7 +579,7 @@ std::unique_ptr<cli::Results> cli::ArgumentParser::parse(const std::string& prog
             case cli::SUB_OPTIONS:
             {
                 if (optionsStr.empty())
-                    parseError(str::Format("invalid sub option: [%s]", argVar.c_str()));
+                    parseError(str::Format("invalid sub option: [%s]", argVar));
 
                 auto v_ = std::make_unique<cli::Value>();
                 auto v = currentResults->hasValue(optionsStr) ? currentResults->getValue(optionsStr) : v_.get();
@@ -706,7 +706,7 @@ std::unique_ptr<cli::Results> cli::ArgumentParser::parse(const std::string& prog
             }
             if (!isValid)
             {
-                parseError(str::Format("invalid option for [%s]", argVar.c_str()));
+                parseError(str::Format("invalid option for [%s]", argVar));
             }
         }
     }
diff --git a/externals/coda-oss/modules/c++/io/include/io/BufferViewStream.h b/externals/coda-oss/modules/c++/io/include/io/BufferViewStream.h
index beb00d23a2..5f71ae46ca 100644
--- a/externals/coda-oss/modules/c++/io/include/io/BufferViewStream.h
+++ b/externals/coda-oss/modules/c++/io/include/io/BufferViewStream.h
@@ -191,7 +191,7 @@ void BufferViewStream<T>::write(const void* buffer, size_t numBytes)
     {
         std::ostringstream msg;
         msg << "Write of size " << numBytes << " runs out of bounds.";
-        throw except::Exception(Ctxt(msg.str()));
+        throw except::Exception(Ctxt(msg));
     }
 
     ::memcpy(mBufferView.data + mPosition, buffer, numBytes);
diff --git a/externals/coda-oss/modules/c++/io/include/io/FileUtils.h b/externals/coda-oss/modules/c++/io/include/io/FileUtils.h
index d8305fc0c5..927aeb4f5b 100644
--- a/externals/coda-oss/modules/c++/io/include/io/FileUtils.h
+++ b/externals/coda-oss/modules/c++/io/include/io/FileUtils.h
@@ -62,7 +62,7 @@ inline void move(const std::string& path,
         oss << "Move Failed: Could not move source [" <<
             path << "] to destination [" <<
             newPath << "]";
-        throw except::Exception(Ctxt(oss.str()));
+        throw except::Exception(Ctxt(oss));
     }
 }
 
diff --git a/externals/coda-oss/modules/c++/io/source/FileUtils.cpp b/externals/coda-oss/modules/c++/io/source/FileUtils.cpp
index 5c61540576..e0aaf24ea7 100644
--- a/externals/coda-oss/modules/c++/io/source/FileUtils.cpp
+++ b/externals/coda-oss/modules/c++/io/source/FileUtils.cpp
@@ -122,7 +122,7 @@ void io::copy(const std::string& path,
             oss << "Copy Failed: Could not copy source [" <<
                 path << "] to destination [" <<
                 newFile << "]";
-            throw except::Exception(Ctxt(oss.str()));
+            throw except::Exception(Ctxt(oss));
         }
     }
 }
@@ -133,8 +133,7 @@ std::string io::FileUtils::createFile(std::string dirname,
     sys::OS os;
 
     if (!os.exists(dirname))
-        throw except::IOException(Ctxt(str::Format("Directory does not exist: %s",
-                                            dirname.c_str())));
+        throw except::IOException(Ctxt(str::Format("Directory does not exist: %s", dirname)));
 
     str::trim(filename);
 
diff --git a/externals/coda-oss/modules/c++/io/source/InputStream.cpp b/externals/coda-oss/modules/c++/io/source/InputStream.cpp
index e39ac48a6b..b85dcf37d4 100644
--- a/externals/coda-oss/modules/c++/io/source/InputStream.cpp
+++ b/externals/coda-oss/modules/c++/io/source/InputStream.cpp
@@ -37,14 +37,14 @@ sys::SSize_T InputStream::read(void* buffer,
         {
             std::ostringstream ostr;
             ostr << "Tried to read " << len << " bytes but read failed";
-            throw except::IOException(Ctxt(ostr.str()));
+            throw except::IOException(Ctxt(ostr));
         }
         else if (numBytes != static_cast<sys::SSize_T>(len))
         {
             std::ostringstream ostr;
             ostr << "Tried to read " << len << " bytes but only read "
                  << numBytes << " bytes";
-            throw except::IOException(Ctxt(ostr.str()));
+            throw except::IOException(Ctxt(ostr));
         }
     }
 
diff --git a/externals/coda-oss/modules/c++/io/source/MMapInputStream.cpp b/externals/coda-oss/modules/c++/io/source/MMapInputStream.cpp
index e1391083a5..35959ef01f 100644
--- a/externals/coda-oss/modules/c++/io/source/MMapInputStream.cpp
+++ b/externals/coda-oss/modules/c++/io/source/MMapInputStream.cpp
@@ -28,7 +28,7 @@ void io::MMapInputStream::open(const std::string& fname, char* flags)
     //    std::cout << mLength << std::endl;
     mFile = fopen(fname.c_str(), "r");
     if (!mFile)
-        throw sys::SystemException(str::Format("Failure while opening file: %s", fname.c_str()));
+        throw sys::SystemException(str::Format("Failure while opening file: %s", fname));
 
     _map();
 
diff --git a/externals/coda-oss/modules/c++/io/source/StreamSplitter.cpp b/externals/coda-oss/modules/c++/io/source/StreamSplitter.cpp
index 57d6a2f603..dbef8edc2e 100644
--- a/externals/coda-oss/modules/c++/io/source/StreamSplitter.cpp
+++ b/externals/coda-oss/modules/c++/io/source/StreamSplitter.cpp
@@ -55,7 +55,7 @@ StreamSplitter::StreamSplitter(io::InputStream& inputStream,
         std::ostringstream os;
         os << "bufferSize must be >= twice the delimiter size + 1 byte. "
            << "Normally it should be much larger for good performance.";
-        throw except::InvalidArgumentException(Ctxt(os.str()));
+        throw except::InvalidArgumentException(Ctxt(os));
     }
 }
 
diff --git a/externals/coda-oss/modules/c++/io/tests/serializeTest1.cpp b/externals/coda-oss/modules/c++/io/tests/serializeTest1.cpp
index 01fb74dd89..5229fb2652 100644
--- a/externals/coda-oss/modules/c++/io/tests/serializeTest1.cpp
+++ b/externals/coda-oss/modules/c++/io/tests/serializeTest1.cpp
@@ -60,9 +60,9 @@ class A : public Serializable
 	string vec_2 = fillString(is);
 
 	assert(classType == "Class A");
-	dbg.writeln(str::Format("vec[0] = %s", vec_0.c_str()));
-	dbg.writeln(str::Format("vec[1] = %s", vec_1.c_str()));
-	dbg.writeln(str::Format("vec[2] = %s", vec_2.c_str()));
+	dbg.writeln(str::Format("vec[0] = %s", vec_0));
+	dbg.writeln(str::Format("vec[1] = %s", vec_1));
+	dbg.writeln(str::Format("vec[2] = %s", vec_2));
 
 	vec[0] = str::toType<float>(vec_0);
 	vec[1] = str::toType<float>(vec_1);
diff --git a/externals/coda-oss/modules/c++/logging/include/logging/Enums.h b/externals/coda-oss/modules/c++/logging/include/logging/Enums.h
index 8569a8c49f..9175a8126d 100644
--- a/externals/coda-oss/modules/c++/logging/include/logging/Enums.h
+++ b/externals/coda-oss/modules/c++/logging/include/logging/Enums.h
@@ -93,7 +93,7 @@ struct LogLevel final
         else if (s == "SEVERE")
             value = LOG_CRITICAL;
         else
-            throw except::InvalidFormatException(Ctxt(str::Format("Invalid enum value: %s", s.c_str())));
+            throw except::InvalidFormatException(Ctxt(str::Format("Invalid enum value: %s", s)));
     }
 
     //! int constructor
diff --git a/externals/coda-oss/modules/c++/math.poly/include/math/poly/Fit.h b/externals/coda-oss/modules/c++/math.poly/include/math/poly/Fit.h
index 0a3978fdbc..3e54777bf7 100644
--- a/externals/coda-oss/modules/c++/math.poly/include/math/poly/Fit.h
+++ b/externals/coda-oss/modules/c++/math.poly/include/math/poly/Fit.h
@@ -82,7 +82,7 @@ template<typename Vector_T> OneD<double> fit(const Vector_T& x,
               << sizeX << " points for an order-" << order
               << "fit)!  You should really have at least (order+1) = "
               << (order+1) << " points for this to do what you expect.";
-        throw except::Exception(Ctxt(excSS.str()));
+        throw except::Exception(Ctxt(excSS));
     }
     
     // Compute mean value
@@ -206,7 +206,7 @@ inline math::poly::TwoD<double> fit(const math::linear::Matrix2D<double>& x,
               <<  x.size() << " points for a " << acols << "-coefficient fit)!"
               << " You should really have at least (orderX+1)*(orderY+1) = "
               << acols << " points for this to do what you expect.";
-        throw except::Exception(Ctxt(excSS.str()));
+        throw except::Exception(Ctxt(excSS));
     }
     
 
diff --git a/externals/coda-oss/modules/c++/math.poly/include/math/poly/OneD.hpp b/externals/coda-oss/modules/c++/math.poly/include/math/poly/OneD.hpp
index 67fb59b7b8..9aa0253540 100644
--- a/externals/coda-oss/modules/c++/math.poly/include/math/poly/OneD.hpp
+++ b/externals/coda-oss/modules/c++/math.poly/include/math/poly/OneD.hpp
@@ -178,10 +178,9 @@ OneD<_T>::operator [] (size_t i)
     }
     else
     {
-        std::stringstream str;
-        str << "index: " << i << " not within range [0..."
-            << mCoef.size() << ")";
-        throw except::IndexOutOfRangeException(Ctxt(str.str()));
+        std::ostringstream str;
+        str << "index: " << i << " not within range [0..." << mCoef.size() << ")";
+        throw except::IndexOutOfRangeException(Ctxt(str));
     }
 }
 
@@ -196,9 +195,9 @@ OneD<_T>::operator [] (size_t i) const
    }
    else
    {
-      std::stringstream str;
+      std::ostringstream str;
       str << "idx(" << i << ") not within range [0..." << mCoef.size() << ")";
-      throw except::IndexOutOfRangeException(Ctxt(str.str()));
+      throw except::IndexOutOfRangeException(Ctxt(str));
    }
 }
 
diff --git a/externals/coda-oss/modules/c++/math.poly/include/math/poly/TwoD.hpp b/externals/coda-oss/modules/c++/math.poly/include/math/poly/TwoD.hpp
index 2a26275404..87d7f72178 100644
--- a/externals/coda-oss/modules/c++/math.poly/include/math/poly/TwoD.hpp
+++ b/externals/coda-oss/modules/c++/math.poly/include/math/poly/TwoD.hpp
@@ -187,11 +187,9 @@ TwoD<_T>::operator [] (size_t i) const
     }
     else
     {
-        std::stringstream str;
-        str << "index:" << i << " not within range [0..."
-            << mCoef.size() << ")";
-
-        throw except::IndexOutOfRangeException(Ctxt(str.str()));
+        std::ostringstream str;
+        str << "index:" << i << " not within range [0..." << mCoef.size() << ")";
+        throw except::IndexOutOfRangeException(Ctxt(str));
     }
     return ret;
 }
@@ -206,10 +204,9 @@ TwoD<_T>::operator [] (size_t i)
     }
     else
     {
-        std::stringstream str;
-        str << "index: " << i << " not within range [0..."
-            << mCoef.size() << ")";
-        throw except::IndexOutOfRangeException(Ctxt(str.str()));
+        std::ostringstream str;
+        str << "index: " << i << " not within range [0..." << mCoef.size() << ")";
+        throw except::IndexOutOfRangeException(Ctxt(str));
     }
 }
 
diff --git a/externals/coda-oss/modules/c++/mem/include/mem/BufferView.h b/externals/coda-oss/modules/c++/mem/include/mem/BufferView.h
index 02816c5260..55997392b2 100644
--- a/externals/coda-oss/modules/c++/mem/include/mem/BufferView.h
+++ b/externals/coda-oss/modules/c++/mem/include/mem/BufferView.h
@@ -70,7 +70,7 @@ struct BufferView
             oss << "BufferView::section() called with sectionSize: " << sectionSize << " when";
             oss << " there were only " << size << " elements in the BufferView";
             
-            throw except::Exception(Ctxt(oss.str()));
+            throw except::Exception(Ctxt(oss));
         } 
 
         BufferView<T> newSection(data, sectionSize);
diff --git a/externals/coda-oss/modules/c++/mem/include/mem/ScratchMemory.hpp b/externals/coda-oss/modules/c++/mem/include/mem/ScratchMemory.hpp
index 45c6fcd261..7b22af8354 100644
--- a/externals/coda-oss/modules/c++/mem/include/mem/ScratchMemory.hpp
+++ b/externals/coda-oss/modules/c++/mem/include/mem/ScratchMemory.hpp
@@ -52,7 +52,7 @@ inline void ScratchMemory::put<sys::ubyte>(const std::string& key,
     {
         std::ostringstream oss;
         oss << "Scratch memory space was already reserved for " << key;
-        throw except::Exception(Ctxt(oss.str()));
+        throw except::Exception(Ctxt(oss));
     }
     mSegments.insert(
             iterSeg,
diff --git a/externals/coda-oss/modules/c++/mem/source/ScratchMemory.cpp b/externals/coda-oss/modules/c++/mem/source/ScratchMemory.cpp
index a3f162daa0..4677b1da99 100644
--- a/externals/coda-oss/modules/c++/mem/source/ScratchMemory.cpp
+++ b/externals/coda-oss/modules/c++/mem/source/ScratchMemory.cpp
@@ -212,9 +212,8 @@ const ScratchMemory::Segment& ScratchMemory::lookupSegment(
     if (mBuffer.data == nullptr)
     {
         std::ostringstream oss;
-        oss << "Tried to get scratch memory for \"" << key
-            << "\" before running setup.";
-        throw except::Exception(Ctxt(oss.str()));
+        oss << "Tried to get scratch memory for \"" << key << "\" before running setup.";
+        throw except::Exception(Ctxt(oss));
     }
 
     std::map<std::string, Segment>::const_iterator iterSeg = mSegments.find(key);
@@ -222,7 +221,7 @@ const ScratchMemory::Segment& ScratchMemory::lookupSegment(
     {
         std::ostringstream oss;
         oss << "Scratch memory segment was not found for \"" << key << "\"";
-        throw except::Exception(Ctxt(oss.str()));
+        throw except::Exception(Ctxt(oss));
     }
 
     const Segment& segment = iterSeg->second;
@@ -230,9 +229,8 @@ const ScratchMemory::Segment& ScratchMemory::lookupSegment(
     {
         std::ostringstream oss;
         oss << "Trying to get buffer index " << indexBuffer << " for \""
-            << key << "\", which has only " << segment.buffers.size()
-            << " buffers";
-        throw except::Exception(Ctxt(oss.str()));
+            << key << "\", which has only " << segment.buffers.size() << " buffers";
+        throw except::Exception(Ctxt(oss));
     }
     return segment;
 }
diff --git a/externals/coda-oss/modules/c++/mt/include/mt/BalancedRunnable1D.h b/externals/coda-oss/modules/c++/mt/include/mt/BalancedRunnable1D.h
index c7af782fb7..3ee200e04d 100644
--- a/externals/coda-oss/modules/c++/mt/include/mt/BalancedRunnable1D.h
+++ b/externals/coda-oss/modules/c++/mt/include/mt/BalancedRunnable1D.h
@@ -159,7 +159,7 @@ void runBalanced1D(size_t numElements,
         std::ostringstream ostr;
         ostr << "Got " << numThreads << " threads but " << ops.size()
              << " functors";
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     if (numThreads <= 1)
diff --git a/externals/coda-oss/modules/c++/mt/include/mt/Runnable1D.h b/externals/coda-oss/modules/c++/mt/include/mt/Runnable1D.h
index dbcde3aada..fb277b1e8c 100644
--- a/externals/coda-oss/modules/c++/mt/include/mt/Runnable1D.h
+++ b/externals/coda-oss/modules/c++/mt/include/mt/Runnable1D.h
@@ -75,7 +75,7 @@ void run1D(size_t numElements, size_t numThreads, const std::vector<OpT>& ops)
         std::ostringstream ostr;
         ostr << "Got " << numThreads << " threads but " << ops.size()
              << " functors";
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     if (numThreads <= 1)
diff --git a/externals/coda-oss/modules/c++/mt/include/mt/WorkSharingBalancedRunnable1D.h b/externals/coda-oss/modules/c++/mt/include/mt/WorkSharingBalancedRunnable1D.h
index dd8e4553de..95f36e6a75 100644
--- a/externals/coda-oss/modules/c++/mt/include/mt/WorkSharingBalancedRunnable1D.h
+++ b/externals/coda-oss/modules/c++/mt/include/mt/WorkSharingBalancedRunnable1D.h
@@ -238,7 +238,7 @@ void runWorkSharingBalanced1D(size_t numElements,
         std::ostringstream ostr;
         ostr << "Got " << numThreads << " threads but " << ops.size()
              << " functors";
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     std::vector<size_t> threadPoolEndElements;
diff --git a/externals/coda-oss/modules/c++/mt/source/CPUAffinityInitializerLinux.cpp b/externals/coda-oss/modules/c++/mt/source/CPUAffinityInitializerLinux.cpp
index 7da70537a7..2f728fad97 100644
--- a/externals/coda-oss/modules/c++/mt/source/CPUAffinityInitializerLinux.cpp
+++ b/externals/coda-oss/modules/c++/mt/source/CPUAffinityInitializerLinux.cpp
@@ -66,7 +66,7 @@ struct AvailableCPUProvider final : public AbstractNextCPUProviderLinux
         {
             std::ostringstream msg;
             msg << "No more CPUs available (size = " << mCPUs.size() << ")";
-            throw except::Exception(Ctxt(msg.str()));
+            throw except::Exception(Ctxt(msg));
         }
 
         std::unique_ptr<sys::ScopedCPUMaskUnix> mask(new sys::ScopedCPUMaskUnix());
diff --git a/externals/coda-oss/modules/c++/net/include/net/Socket.h b/externals/coda-oss/modules/c++/net/include/net/Socket.h
index 7d75eae466..024af735c5 100644
--- a/externals/coda-oss/modules/c++/net/include/net/Socket.h
+++ b/externals/coda-oss/modules/c++/net/include/net/Socket.h
@@ -170,7 +170,7 @@ class Socket
 
             std::ostringstream oss;
             oss << "Socket setOptions failure: " << err.toString();
-            throw sys::SocketException(Ctxt(oss.str()));
+            throw sys::SocketException(Ctxt(oss));
         }
     }
 
diff --git a/externals/coda-oss/modules/c++/net/source/DaemonUnix.cpp b/externals/coda-oss/modules/c++/net/source/DaemonUnix.cpp
index 797f515788..af0a1e0bf6 100644
--- a/externals/coda-oss/modules/c++/net/source/DaemonUnix.cpp
+++ b/externals/coda-oss/modules/c++/net/source/DaemonUnix.cpp
@@ -258,12 +258,12 @@ void DaemonUnix::redirectStreamsTo(const std::string& filename)
     if (openFileFor(STDOUT_FILENO, filename, O_WRONLY|O_CREAT|O_TRUNC) < 0)
     {
         throw except::Exception(
-            Ctxt(str::Format("Failed to open file %s for STDOUT.", filename.c_str())));
+            Ctxt(str::Format("Failed to open file %s for STDOUT.", filename)));
     }
     if (openFileFor(STDERR_FILENO, filename, O_WRONLY|O_CREAT|O_TRUNC) < 0)
     {
         throw except::Exception(
-            Ctxt(str::Format("Failed to open file %s for STDERR.", filename.c_str())));
+            Ctxt(str::Format("Failed to open file %s for STDERR.", filename)));
     }
 }
 
diff --git a/externals/coda-oss/modules/c++/net/source/Socket.cpp b/externals/coda-oss/modules/c++/net/source/Socket.cpp
index 4fa436453c..b7b8627c5d 100644
--- a/externals/coda-oss/modules/c++/net/source/Socket.cpp
+++ b/externals/coda-oss/modules/c++/net/source/Socket.cpp
@@ -104,7 +104,7 @@ size_t net::Socket::recv(void* b, size_t len, int flags)
         oss << "When receiving " << str::toString(len) << " bytes: " << 
             err.toString(); 
 
-        throw sys::SocketException(Ctxt(oss.str()));
+        throw sys::SocketException(Ctxt(oss));
     }
     else if (numBytes == 0)
     {
@@ -170,7 +170,7 @@ void net::Socket::send(const void* b, size_t len, int flags)
         oss << "Tried sending " << len << " bytes, " <<
                 numBytes << " sent: " <<  err.toString();
 
-        throw sys::SocketException(Ctxt(oss.str()));
+        throw sys::SocketException(Ctxt(oss));
     }
 }
 
@@ -193,6 +193,6 @@ void net::Socket::sendTo(const SocketAddress& address,
         oss << "Tried sending " << len << " bytes, " << numBytes << " sent: "
             <<  err.toString();
 
-        throw sys::SocketException(Ctxt(oss.str()));
+        throw sys::SocketException(Ctxt(oss));
     }
 }
diff --git a/externals/coda-oss/modules/c++/polygon/source/PolygonMask.cpp b/externals/coda-oss/modules/c++/polygon/source/PolygonMask.cpp
index d9a729feff..6ad904aa2f 100644
--- a/externals/coda-oss/modules/c++/polygon/source/PolygonMask.cpp
+++ b/externals/coda-oss/modules/c++/polygon/source/PolygonMask.cpp
@@ -134,9 +134,8 @@ PolygonMask::PolygonMask(const std::vector<types::RowCol<double> >& points,
                 // happen.
                 std::ostringstream ostr;
                 ostr << "Requires a convex polygon but these points produced "
-                     << intersectionsVec.size() << " intersections for row "
-                     << row;
-                throw except::Exception(Ctxt(ostr.str()));
+                     << intersectionsVec.size() << " intersections for row " << row;
+                throw except::Exception(Ctxt(ostr));
             }
         }
 
diff --git a/externals/coda-oss/modules/c++/re/source/RegexPCRE.cpp b/externals/coda-oss/modules/c++/re/source/RegexPCRE.cpp
index 94fd0b9ec9..01b0393b3f 100644
--- a/externals/coda-oss/modules/c++/re/source/RegexPCRE.cpp
+++ b/externals/coda-oss/modules/c++/re/source/RegexPCRE.cpp
@@ -137,7 +137,7 @@ class ScopedMatchData
             ostr << "Match: Match substring out of range ("
                  << index << ", " << end << ") for string of length "
                  << str.length();
-            throw re::RegexException(Ctxt(ostr.str()));
+            throw re::RegexException(Ctxt(ostr));
         }
 
         const size_t subStringLength = end - index;
@@ -225,7 +225,7 @@ Regex& Regex::compile(const std::string& pattern)
         std::ostringstream ostr;
         ostr << "PCRE compilation failed at offset " << errorOffset
              << ": " << getErrorMessage(errorCode);
-        throw RegexException(Ctxt(ostr.str()));
+        throw RegexException(Ctxt(ostr));
     }
 
     return *this;
diff --git a/externals/coda-oss/modules/c++/sys/source/FileWin32.cpp b/externals/coda-oss/modules/c++/sys/source/FileWin32.cpp
index cf30c9f6cc..d1ed79a67d 100644
--- a/externals/coda-oss/modules/c++/sys/source/FileWin32.cpp
+++ b/externals/coda-oss/modules/c++/sys/source/FileWin32.cpp
@@ -58,8 +58,7 @@ void sys::File::create(const std::string& str,
     create(std::nothrow, str, accessFlags, creationFlags);
     if (mHandle == INVALID_HANDLE_VALUE)
     {
-        throw sys::SystemException(
-                Ctxt(str::Format("Error opening file: [%s]", str.c_str())));
+        throw sys::SystemException(Ctxt(str::Format("Error opening file: [%s]", str)));
     }
 }
 
@@ -169,8 +168,7 @@ sys::Off_T sys::File::lastModifiedTime()
         return (sys::Off_T)stInMillis;
     }
     throw sys::SystemException(Ctxt(
-                    str::Format("Error getting last modified time for path %s",
-                            mPath.c_str())));
+                    str::Format("Error getting last modified time for path %s", mPath)));
 }
 
 void sys::File::flush()
diff --git a/externals/coda-oss/modules/c++/sys/source/OSUnix.cpp b/externals/coda-oss/modules/c++/sys/source/OSUnix.cpp
index d1806010d8..9a3cb61b9a 100644
--- a/externals/coda-oss/modules/c++/sys/source/OSUnix.cpp
+++ b/externals/coda-oss/modules/c++/sys/source/OSUnix.cpp
@@ -122,7 +122,7 @@ std::set<std::string> get_unique_thread_siblings()
                 std::ostringstream msg;
                 msg << "Unable to open thread siblings file "
                     << tsPath.getPath();
-                throw except::Exception(Ctxt(msg.str()));
+                throw except::Exception(Ctxt(msg));
             }
 
             std::string tsContents;
@@ -176,7 +176,7 @@ void sys::OSUnix::removeFile(const std::string& pathname) const
         oss << "Failure removing file [" <<  pathname <<
             "] with error [" << err.toString() << "]";
 
-        throw except::Exception(Ctxt(oss.str()));
+        throw except::Exception(Ctxt(oss));
     }
 }
 
@@ -189,7 +189,7 @@ void sys::OSUnix::removeDirectory(const std::string& pathname) const
         oss << "Failure removing directory [" <<  pathname <<
             "] with error [" << err.toString() << "]";
 
-        throw except::Exception(Ctxt(oss.str()));
+        throw except::Exception(Ctxt(oss));
     }
 }
 
@@ -463,7 +463,7 @@ void sys::OSUnix::removeSymlink(const std::string& symlinkPathname) const
 		oss << "Failure removing symlink [" <<  symlinkPathname <<
 			"] with error [" << err.toString() << "]";
 
-		throw except::Exception(Ctxt(oss.str()));
+		throw except::Exception(Ctxt(oss));
 	}
 }
 
diff --git a/externals/coda-oss/modules/c++/sys/source/OSWin32.cpp b/externals/coda-oss/modules/c++/sys/source/OSWin32.cpp
index bde4cb5d28..57145274ff 100644
--- a/externals/coda-oss/modules/c++/sys/source/OSWin32.cpp
+++ b/externals/coda-oss/modules/c++/sys/source/OSWin32.cpp
@@ -112,7 +112,7 @@ void sys::OSWin32::removeFile(const std::string& pathname) const
         oss << "Failure removing file [" <<  pathname <<
             "] with error [" << err.toString() << "]";
 
-        throw except::Exception(Ctxt(oss.str()));
+        throw except::Exception(Ctxt(oss));
     }
 }
 
@@ -125,7 +125,7 @@ void sys::OSWin32::removeDirectory(const std::string& pathname) const
         oss << "Failure removing directory [" <<  pathname <<
             "] with error [" << err.toString() << "]";
 
-        throw except::Exception(Ctxt(oss.str()));
+        throw except::Exception(Ctxt(oss));
     }
 }
 
@@ -414,7 +414,7 @@ void sys::OSWin32::removeSymlink(const std::string& symlinkPathname) const
         oss << "Failure removing symlink [" <<  symlinkPathname <<
             "] with error [" << err.toString() << "]";
 
-        throw except::Exception(Ctxt(oss.str()));
+        throw except::Exception(Ctxt(oss));
     }
 }
 
diff --git a/externals/coda-oss/modules/c++/sys/source/Path.cpp b/externals/coda-oss/modules/c++/sys/source/Path.cpp
index b775585af2..4c91e6d18f 100644
--- a/externals/coda-oss/modules/c++/sys/source/Path.cpp
+++ b/externals/coda-oss/modules/c++/sys/source/Path.cpp
@@ -279,7 +279,7 @@ std::vector<std::string> Path::list(const std::string& path)
         std::ostringstream oss;
         oss << "'" << path
                 << "' does not exist or is not a valid directory";
-        throw except::Exception(Ctxt(oss.str()));
+        throw except::Exception(Ctxt(oss));
     }
     std::vector<std::string> listing;
     Directory directory;
diff --git a/externals/coda-oss/modules/c++/sys/source/ScopedCPUAffinityUnix.cpp b/externals/coda-oss/modules/c++/sys/source/ScopedCPUAffinityUnix.cpp
index e409b3b03f..07f67cfe42 100644
--- a/externals/coda-oss/modules/c++/sys/source/ScopedCPUAffinityUnix.cpp
+++ b/externals/coda-oss/modules/c++/sys/source/ScopedCPUAffinityUnix.cpp
@@ -56,7 +56,7 @@ void ScopedCPUMaskUnix::initialize(int numCPUs)
     {
         std::ostringstream msg;
         msg << "Failed to allocate CPU mask for " << numCPUs << "CPUs";
-        throw except::Exception(Ctxt(msg.str()));
+        throw except::Exception(Ctxt(msg));
     }
 
     CPU_ZERO_S(mSize, mMask);
@@ -122,7 +122,7 @@ ScopedCPUAffinityUnix::ScopedCPUAffinityUnix() :
         default:
             msg << " Unknown cause.";
         }
-        throw except::Exception(Ctxt(msg.str()));
+        throw except::Exception(Ctxt(msg));
     }
 }
 }
diff --git a/externals/coda-oss/modules/c++/tiff/include/tiff/IFD.h b/externals/coda-oss/modules/c++/tiff/include/tiff/IFD.h
index 4975bdaaa8..9120f581a5 100644
--- a/externals/coda-oss/modules/c++/tiff/include/tiff/IFD.h
+++ b/externals/coda-oss/modules/c++/tiff/include/tiff/IFD.h
@@ -155,8 +155,7 @@ class IFD : public io::Serializable
         const tiff::IFDEntry *mapEntry = tiff::KnownTagsRegistry::getInstance()[name];
         //we can't add it if we don't know about it
         if (!mapEntry)
-            throw except::Exception(Ctxt(str::Format(
-                                    "Unable to add IFD Entry: unknown tag [%s]", name.c_str())));
+            throw except::Exception(Ctxt(str::Format("Unable to add IFD Entry: unknown tag [%s]", name)));
 
         const auto id = mapEntry->getTagID();
         const auto type = mapEntry->getType();
diff --git a/externals/coda-oss/modules/c++/tiff/source/IFD.cpp b/externals/coda-oss/modules/c++/tiff/source/IFD.cpp
index bb9d80e7dc..09a5396a26 100644
--- a/externals/coda-oss/modules/c++/tiff/source/IFD.cpp
+++ b/externals/coda-oss/modules/c++/tiff/source/IFD.cpp
@@ -90,8 +90,7 @@ void tiff::IFD::addEntry(const std::string& name)
     tiff::IFDEntry *mapEntry = tiff::KnownTagsRegistry::getInstance()[name];
     // we can't add it b/c we don't know about this tag
     if (!mapEntry)
-        throw except::Exception(Ctxt(str::Format(
-                                "Unable to add IFD Entry: unknown tag [%s]", name.c_str())));
+        throw except::Exception(Ctxt(str::Format("Unable to add IFD Entry: unknown tag [%s]", name)));
 
     unsigned short id = mapEntry->getTagID();
 
diff --git a/externals/coda-oss/modules/c++/xml.lite/source/Attributes.cpp b/externals/coda-oss/modules/c++/xml.lite/source/Attributes.cpp
index 4032f86fc0..aff2572562 100644
--- a/externals/coda-oss/modules/c++/xml.lite/source/Attributes.cpp
+++ b/externals/coda-oss/modules/c++/xml.lite/source/Attributes.cpp
@@ -125,8 +125,7 @@ std::string xml::lite::Attributes::getValue(const std::string& qname) const
     std::string retval;
     if (!getValue(qname, retval))
     {
-        throw except::NoSuchKeyException(Ctxt(str::Format("QName '%s' could not be found",
-                                                   qname.c_str())));
+        throw except::NoSuchKeyException(Ctxt(str::Format("QName '%s' could not be found", qname)));
     }
     
     return retval;  
diff --git a/externals/coda-oss/modules/c++/xml.lite/source/ValidatorXerces.cpp b/externals/coda-oss/modules/c++/xml.lite/source/ValidatorXerces.cpp
index 0d5280881f..3950d12422 100644
--- a/externals/coda-oss/modules/c++/xml.lite/source/ValidatorXerces.cpp
+++ b/externals/coda-oss/modules/c++/xml.lite/source/ValidatorXerces.cpp
@@ -181,7 +181,7 @@ ValidatorXerces::ValidatorXerces(
         {
             std::ostringstream oss;
             oss << "Error: Failure to load schema " << schema;
-            log->warn(Ctxt(oss.str()));
+            log->warn(Ctxt(oss));
         }
     }
 
diff --git a/externals/nitro/modules/c++/nitf/source/ByteProvider.cpp b/externals/nitro/modules/c++/nitf/source/ByteProvider.cpp
index c908b2a8c5..2b3b8206a7 100644
--- a/externals/nitro/modules/c++/nitf/source/ByteProvider.cpp
+++ b/externals/nitro/modules/c++/nitf/source/ByteProvider.cpp
@@ -249,18 +249,16 @@ void  ByteProvider::getFileLayout_(const nitf::Record& inRecord,
             {
                 std::ostringstream ostr;
                 ostr << "First image segment had " << mNumCols
-                     << " columns but image segment " << ii << " has "
-                     << numCols;
-                throw except::Exception(Ctxt(ostr.str()));
+                     << " columns but image segment " << ii << " has " << numCols;
+                throw except::Exception(Ctxt(ostr));
             }
 
             if (numBytesPerPixel != mNumBytesPerPixel)
             {
                 std::ostringstream ostr;
                 ostr << "First image segment had " << mNumBytesPerPixel
-                     << " bytes/pxeil but image segment " << ii << " has "
-                     << numBytesPerPixel;
-                throw except::Exception(Ctxt(ostr.str()));
+                     << " bytes/pxeil but image segment " << ii << " has " << numBytesPerPixel;
+                throw except::Exception(Ctxt(ostr));
             }
         }
 
@@ -287,7 +285,7 @@ void  ByteProvider::getFileLayout_(const nitf::Record& inRecord,
         std::ostringstream ostr;
         ostr << "Record has " << numDESs << " DESs but "
              << desData.size() << " DES data was sent in";
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     std::vector<size_t> desSubheaderLengths(numDESs);
@@ -415,7 +413,7 @@ void ByteProvider::checkBlocking(size_t seg,
             ostr << "Trying to write starting at segment " << seg
                  << "'s row " << segStartRowToWrite
                  << " which is not a multiple of " << numRowsPerBlock;
-            throw except::Exception(Ctxt(ostr.str()));
+            throw except::Exception(Ctxt(ostr));
         }
 
         // Need to end on a block boundary or the end of the segment
@@ -429,7 +427,7 @@ void ByteProvider::checkBlocking(size_t seg,
                  << " which is not a multiple of " << numRowsPerBlock
                  << " (segment has start = " << imageSegmentInfo.firstRow
                  << ", num = " << imageSegmentInfo.numRows << ")";
-            throw except::Exception(Ctxt(ostr.str()));
+            throw except::Exception(Ctxt(ostr));
         }
     }
 }
diff --git a/externals/nitro/modules/c++/nitf/source/CompressedByteProvider.cpp b/externals/nitro/modules/c++/nitf/source/CompressedByteProvider.cpp
index bb15773b09..7cee92b71d 100644
--- a/externals/nitro/modules/c++/nitf/source/CompressedByteProvider.cpp
+++ b/externals/nitro/modules/c++/nitf/source/CompressedByteProvider.cpp
@@ -70,9 +70,8 @@ void CompressedByteProvider::initialize_(const Record& record,
     {
         std::ostringstream oss;
         oss << "NITF header metadata contains " << numImages << " images, "
-            << "but block sizes provided for " << bytesPerBlock.size()
-            << " images.";
-        throw except::Exception(Ctxt(oss.str()));
+            << "but block sizes provided for " << bytesPerBlock.size() << " images.";
+        throw except::Exception(Ctxt(oss));
     }
     mImageDataLengths.resize(numImages);
 
@@ -119,7 +118,7 @@ size_t CompressedByteProvider::countBytesForCompressedImageData(
         ostr << "Trying to get bytes from blocks [" << blockRange.mStartElement
              << ", " << blockRange.endElement() << ") but seg " << seg
              << " only has " << bytesPerBlock.size() << " blocks";
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     size_t numBytes = 0;
@@ -152,7 +151,7 @@ types::Range CompressedByteProvider::findBlocksToWrite(
               << (globalStartRow + numRowsToWrite) << ") from seg " << seg
               << " which contains global rows [" << segmentInfo.firstRow
               << ", " << segmentInfo.endRow() << ")";
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     const size_t startRow = globalStartRow - segmentInfo.firstRow;
@@ -192,7 +191,7 @@ static size_t addImageData_(const std::vector<std::vector<size_t> > mBytesInEach
             std::ostringstream error;
             error << "Internal logic error. blockRange.mStartElement should "
                   << "never be 0 when fileOffset hasn't been set.";
-            throw except::Exception(Ctxt(error.str()));
+            throw except::Exception(Ctxt(error));
         }
 
         fileOffset = mImageSubheaderFileOffsets[seg] + gsl::narrow<nitf::Off>(mImageSubheaders[seg].size());
diff --git a/externals/nitro/modules/c++/nitf/source/ImageBlocker.cpp b/externals/nitro/modules/c++/nitf/source/ImageBlocker.cpp
index 52f8d3da0f..0c4a257053 100644
--- a/externals/nitro/modules/c++/nitf/source/ImageBlocker.cpp
+++ b/externals/nitro/modules/c++/nitf/source/ImageBlocker.cpp
@@ -147,7 +147,7 @@ void ImageBlocker::findSegment(size_t row,
 
     std::ostringstream ostr;
     ostr << "Row " << row << " is out of bounds";
-    throw except::Exception(Ctxt(ostr.str()));
+    throw except::Exception(Ctxt(ostr));
 }
 
 void ImageBlocker::findSegmentRange(size_t startRow,
@@ -177,7 +177,7 @@ void ImageBlocker::findSegmentRange(size_t startRow,
                  << startRowWithinFirstSeg << " within segment " << firstSegIdx
                  << ".  The local row must be a multiple of "
                  << mNumRowsPerBlock[firstSegIdx] << ".";
-            throw except::Exception(Ctxt(ostr.str()));
+            throw except::Exception(Ctxt(ostr));
         }
 
         // Figure out which segment we're ending in
@@ -196,7 +196,7 @@ void ImageBlocker::findSegmentRange(size_t startRow,
             ostr << "Last row " << lastRow << " is local row "
                  << lastRowWithinLastSeg << " within segment " << lastSegIdx
                  << ".  This must land on a full block.";
-            throw except::Exception(Ctxt(ostr.str()));
+            throw except::Exception(Ctxt(ostr));
         }
     }
 }
@@ -396,6 +396,6 @@ size_t ImageBlocker::getSegmentFromGlobalBlockRow(size_t blockRow) const
     std::ostringstream message;
     message << "Requested block row " << blockRow << ", but this image "
         << "only has " << startBlock << " rows of blocks.";
-    throw except::Exception(Ctxt(message.str()));
+    throw except::Exception(Ctxt(message));
 }
 }
diff --git a/externals/nitro/modules/c++/nitf/source/ImageSegmentComputer.cpp b/externals/nitro/modules/c++/nitf/source/ImageSegmentComputer.cpp
index c862958627..7631befb71 100644
--- a/externals/nitro/modules/c++/nitf/source/ImageSegmentComputer.cpp
+++ b/externals/nitro/modules/c++/nitf/source/ImageSegmentComputer.cpp
@@ -105,18 +105,16 @@ ImageSegmentComputer::ImageSegmentComputer(size_t numRows,
     {
         std::ostringstream ostr;
         ostr << "Max rows was set to " << maxRows
-             << " but it cannot be greater than " << ILOC_MAX
-             << " per the NITF spec";
-        throw except::Exception(Ctxt(ostr.str()));
+             << " but it cannot be greater than " << ILOC_MAX << " per the NITF spec";
+        throw except::Exception(Ctxt(ostr));
     }
 
     if (maxSize > NUM_BYTES_MAX)
     {
         std::ostringstream ostr;
         ostr << "Max image segment size was set to " << maxSize
-             << " but it cannot be greater than " << NUM_BYTES_MAX
-             << " per the NITF spec";
-        throw except::Exception(Ctxt(ostr.str()));
+             << " but it cannot be greater than " << NUM_BYTES_MAX << " per the NITF spec";
+        throw except::Exception(Ctxt(ostr));
     }
 
     computeImageInfo();
@@ -152,9 +150,8 @@ void ImageSegmentComputer::computeImageInfo()
     {
         // This should not be possible
         std::ostringstream ostr;
-        ostr << "Image would require " << maxRowsUint64
-             << " rows which is too many";
-        throw except::Exception(Ctxt(ostr.str()));
+        ostr << "Image would require " << maxRowsUint64 << " rows which is too many";
+        throw except::Exception(Ctxt(ostr));
     }
     size_t maxRows(gsl::narrow<size_t>(maxRowsUint64));
 
@@ -163,7 +160,7 @@ void ImageSegmentComputer::computeImageInfo()
         std::ostringstream ostr;
         ostr << "maxNumBytesPerSegment [" << mMaxNumBytesPerSegment
              << "] < bytesPerRow [" << bytesPerRow << "]";
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     // Truncate back to a full block for the maxRows that will actually fit
@@ -180,7 +177,7 @@ void ImageSegmentComputer::computeImageInfo()
                  << ", bytes per row of " << bytesPerRow
                  << ", and rows per block of " << mNumRowsPerBlock
                  << ", cannot fit an entire block into a segment";
-            throw except::Exception(Ctxt(ostr.str()));
+            throw except::Exception(Ctxt(ostr));
         }
     }
 
diff --git a/externals/nitro/modules/c++/nitf/source/J2KCompressor.cpp b/externals/nitro/modules/c++/nitf/source/J2KCompressor.cpp
index 98648338e3..b5e9f4392e 100644
--- a/externals/nitro/modules/c++/nitf/source/J2KCompressor.cpp
+++ b/externals/nitro/modules/c++/nitf/source/J2KCompressor.cpp
@@ -338,10 +338,10 @@ class TileWriter final
                 mEncoder.clearError();
 
                 os << " with openjpeg error: " << opjErrorMsg;
-                throw except::Exception(Ctxt(os.str()));
+                throw except::Exception(Ctxt(os));
             }
 
-            throw except::Exception(Ctxt(os.str()));
+            throw except::Exception(Ctxt(os));
         }
     }
 
@@ -560,7 +560,7 @@ std::span<std::byte> j2k::Compressor::compressRowSubrange(
     {
         std::ostringstream ostr;
         ostr << "Global start row = " << globalStartRow << " must be a multiple of number of rows in tile = " << numRowsInTile;
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     if ((numLocalRows % numRowsInTile != 0) &&
@@ -568,7 +568,7 @@ std::span<std::byte> j2k::Compressor::compressRowSubrange(
     {
         std::ostringstream ostr;
         ostr << "Number of local rows = " << numLocalRows << " must be a multiple of number of rows in tile = " << numRowsInTile;
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     const auto startRowOfTiles = globalStartRow / numRowsInTile;
@@ -600,7 +600,7 @@ std::span<std::byte> j2k::Compressor::compressTileSubrange(
         std::ostringstream ostr;
         ostr << "Require " << numBytesNeeded << " bytes for compression of "
             << numTiles << " tiles but only received " << compressedData.size() << " bytes";
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     auto compressedPtr = compressedData.data();
@@ -649,7 +649,7 @@ std::span<std::byte> j2k::Compressor::compressTileSubrange(
             std::ostringstream os;
             os << "Cannot write " << numBytesThisTile << " bytes for tile " << tileNum << " at byte offset " << numBytesWritten
                 << " - exceeds maximum compressed image size (" << compressedData.size() << " bytes)!";
-            throw except::Exception(Ctxt(os.str()));
+            throw except::Exception(Ctxt(os));
         }
 
         const auto src = tileStream.get();
diff --git a/externals/nitro/modules/c++/nitf/source/J2KEncoder.cpp b/externals/nitro/modules/c++/nitf/source/J2KEncoder.cpp
index b005bb4377..cddbada264 100644
--- a/externals/nitro/modules/c++/nitf/source/J2KEncoder.cpp
+++ b/externals/nitro/modules/c++/nitf/source/J2KEncoder.cpp
@@ -89,7 +89,7 @@ j2k::Encoder::Encoder(Image& image, const CompressionParameters& compressionPara
 
             std::ostringstream os;
             os << "Failed to setup openjpeg encoder with openjpeg error: " << opjErrorMsg;
-            throw except::Exception(Ctxt(os.str()));
+            throw except::Exception(Ctxt(os));
         }
 
         throw except::Exception(Ctxt("Failed to setup openjpeg encoder."));
diff --git a/externals/nitro/modules/c++/nitf/source/J2KImage.cpp b/externals/nitro/modules/c++/nitf/source/J2KImage.cpp
index 9d536c2178..6ec248ed3c 100644
--- a/externals/nitro/modules/c++/nitf/source/J2KImage.cpp
+++ b/externals/nitro/modules/c++/nitf/source/J2KImage.cpp
@@ -40,7 +40,7 @@ j2k::Image::Image(const types::RowCol<size_t>& rawImageDims)
         std::ostringstream os;
         os << "Failed to create an openjpeg image handle using the provided raw image dimensions";
         os << " (rows: "<< rawImageDims.row << ", cols : " << rawImageDims.col << ")!";
-        throw except::Exception(Ctxt(os.str()));
+        throw except::Exception(Ctxt(os));
     }
 
     // set up the image
diff --git a/externals/nitro/modules/c++/nitf/source/J2KStream.cpp b/externals/nitro/modules/c++/nitf/source/J2KStream.cpp
index 7bbd465ae7..49335d5cf7 100644
--- a/externals/nitro/modules/c++/nitf/source/J2KStream.cpp
+++ b/externals/nitro/modules/c++/nitf/source/J2KStream.cpp
@@ -37,7 +37,7 @@ j2k::Stream::Stream(j2k::StreamType streamType, size_t chunkSize)
     {
         std::ostringstream os;
         os << "Failed creating an openjpeg stream with a chunk size of " << chunkSize << " bytes.";
-        throw except::Exception(Ctxt(os.str()));
+        throw except::Exception(Ctxt(os));
     }
 }
 
diff --git a/externals/nitro/modules/c++/nitf/source/NITFBufferList.cpp b/externals/nitro/modules/c++/nitf/source/NITFBufferList.cpp
index c9db90cd1c..fd2339ae46 100644
--- a/externals/nitro/modules/c++/nitf/source/NITFBufferList.cpp
+++ b/externals/nitro/modules/c++/nitf/source/NITFBufferList.cpp
@@ -67,7 +67,7 @@ size_t NITFBufferList::getNumBytesInBlock(
         std::ostringstream ostr;
         ostr << "Block index " << blockIdx << " is out of bounds - only "
              << numBlocks << " blocks with a block size of " << blockSize;
-        throw except::Exception(Ctxt(ostr.str()));
+        throw except::Exception(Ctxt(ostr));
     }
 
     const size_t numBytes = (blockIdx == numBlocks - 1) ?
diff --git a/externals/nitro/modules/c++/nitf/source/TRE.cpp b/externals/nitro/modules/c++/nitf/source/TRE.cpp
index 97f697bb96..dd109d407d 100644
--- a/externals/nitro/modules/c++/nitf/source/TRE.cpp
+++ b/externals/nitro/modules/c++/nitf/source/TRE.cpp
@@ -219,7 +219,7 @@ nitf_Field& TRE::nitf_TRE_getField(const std::string& tag) const
     {
         std::ostringstream msg;
         msg << tag << " is not a recognized field for this TRE";
-        throw except::Exception(Ctxt(msg.str()));
+        throw except::Exception(Ctxt(msg));
     }
     return *field;
 }