diff --git a/examples/pdf-custom-filter.cc b/examples/pdf-custom-filter.cc
index e3cdf16..1a8f14e 100644
--- a/examples/pdf-custom-filter.cc
+++ b/examples/pdf-custom-filter.cc
@@ -179,7 +179,7 @@ class StreamReplacer: public QPDFObjectHandle::StreamDataProvider
 
   private:
     bool maybeReplace(
-        QPDFObjGen const& og,
+        QPDFObjGen og,
         QPDFObjectHandle& stream,
         Pipeline* pipeline,
         QPDFObjectHandle* dict_updates);
@@ -204,10 +204,7 @@ StreamReplacer::StreamReplacer(QPDF* pdf) :
 
 bool
 StreamReplacer::maybeReplace(
-    QPDFObjGen const& og,
-    QPDFObjectHandle& stream,
-    Pipeline* pipeline,
-    QPDFObjectHandle* dict_updates)
+    QPDFObjGen og, QPDFObjectHandle& stream, Pipeline* pipeline, QPDFObjectHandle* dict_updates)
 {
     // As described in the class comments, this method is called twice. Before writing has started
     // pipeline is nullptr, and dict_updates is provided. In this mode, we figure out whether we
diff --git a/include/qpdf/QPDF.hh b/include/qpdf/QPDF.hh
index 6353522..0e79967 100644
--- a/include/qpdf/QPDF.hh
+++ b/include/qpdf/QPDF.hh
@@ -367,13 +367,13 @@ class QPDF
     // Retrieve an object by object ID and generation. Returns an indirect reference to it. The
     // getObject() methods were added for qpdf 11.
     QPDF_DLL
-    QPDFObjectHandle getObject(QPDFObjGen const&);
+    QPDFObjectHandle getObject(QPDFObjGen);
     QPDF_DLL
     QPDFObjectHandle getObject(int objid, int generation);
     // These are older methods, but there is no intention to deprecate
     // them.
     QPDF_DLL
-    QPDFObjectHandle getObjectByObjGen(QPDFObjGen const&);
+    QPDFObjectHandle getObjectByObjGen(QPDFObjGen);
     QPDF_DLL
     QPDFObjectHandle getObjectByID(int objid, int generation);
 
@@ -387,14 +387,14 @@ class QPDF
     // object is treated as a null object. To replace a reserved object, call replaceReserved
     // instead.
     QPDF_DLL
-    void replaceObject(QPDFObjGen const& og, QPDFObjectHandle);
+    void replaceObject(QPDFObjGen og, QPDFObjectHandle);
     QPDF_DLL
     void replaceObject(int objid, int generation, QPDFObjectHandle);
 
     // Swap two objects given by ID. Prior to qpdf 10.2.1, existing QPDFObjectHandle instances that
     // reference them objects not notice the swap, but this was fixed in 10.2.1.
     QPDF_DLL
-    void swapObjects(QPDFObjGen const& og1, QPDFObjGen const& og2);
+    void swapObjects(QPDFObjGen og1, QPDFObjGen og2);
     QPDF_DLL
     void swapObjects(int objid1, int generation1, int objid2, int generation2);
 
@@ -694,7 +694,7 @@ class QPDF
     // into the array returned by getAllPages() for that page. An exception is thrown if the page is
     // not found.
     QPDF_DLL
-    int findPage(QPDFObjGen const& og);
+    int findPage(QPDFObjGen og);
     QPDF_DLL
     int findPage(QPDFObjectHandle& page);
 
@@ -859,7 +859,7 @@ class QPDF
         static bool
         pipeStreamData(
             QPDF* qpdf,
-            QPDFObjGen const& og,
+            QPDFObjGen og,
             qpdf_offset_t offset,
             size_t length,
             QPDFObjectHandle dict,
@@ -964,7 +964,7 @@ class QPDF
         ForeignStreamData(
             std::shared_ptr<EncryptionParameters> encp,
             std::shared_ptr<InputSource> file,
-            QPDFObjGen const& foreign_og,
+            QPDFObjGen foreign_og,
             qpdf_offset_t offset,
             size_t length,
             QPDFObjectHandle local_dict);
@@ -1002,7 +1002,7 @@ class QPDF
         friend class QPDF;
 
       public:
-        StringDecrypter(QPDF* qpdf, QPDFObjGen const& og);
+        StringDecrypter(QPDF* qpdf, QPDFObjGen og);
         ~StringDecrypter() override = default;
         void decryptString(std::string& val) override;
 
@@ -1014,7 +1014,7 @@ class QPDF
     class ResolveRecorder
     {
       public:
-        ResolveRecorder(QPDF* qpdf, QPDFObjGen const& og) :
+        ResolveRecorder(QPDF* qpdf, QPDFObjGen og) :
             qpdf(qpdf),
             iter(qpdf->m->resolving.insert(og).first)
         {
@@ -1054,14 +1054,14 @@ class QPDF
     void insertXrefEntry(int obj, int f0, qpdf_offset_t f1, int f2);
     void insertFreeXrefEntry(QPDFObjGen);
     void insertReconstructedXrefEntry(int obj, qpdf_offset_t f1, int f2);
-    void setLastObjectDescription(std::string const& description, QPDFObjGen const& og);
+    void setLastObjectDescription(std::string const& description, QPDFObjGen og);
     QPDFObjectHandle readTrailer();
     QPDFObjectHandle readObject(std::string const& description, QPDFObjGen og);
     void readStream(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset);
     void validateStreamLineEnd(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset);
     QPDFObjectHandle readObjectInStream(std::shared_ptr<InputSource>& input, int obj);
     size_t recoverStreamLength(
-        std::shared_ptr<InputSource> input, QPDFObjGen const& og, qpdf_offset_t stream_offset);
+        std::shared_ptr<InputSource> input, QPDFObjGen og, qpdf_offset_t stream_offset);
     QPDFTokenizer::Token readToken(InputSource&, size_t max_len = 0);
 
     QPDFObjectHandle readObjectAtOffset(
@@ -1075,15 +1075,15 @@ class QPDF
     void resolveObjectsInStream(int obj_stream_number);
     void stopOnError(std::string const& message);
     QPDFObjGen nextObjGen();
-    QPDFObjectHandle newIndirect(QPDFObjGen const&, std::shared_ptr<QPDFObject> const&);
+    QPDFObjectHandle newIndirect(QPDFObjGen, std::shared_ptr<QPDFObject> const&);
     QPDFObjectHandle makeIndirectFromQPDFObject(std::shared_ptr<QPDFObject> const& obj);
-    bool isCached(QPDFObjGen const& og);
-    bool isUnresolved(QPDFObjGen const& og);
+    bool isCached(QPDFObjGen og);
+    bool isUnresolved(QPDFObjGen og);
     std::shared_ptr<QPDFObject> getObjectForParser(int id, int gen, bool parse_pdf);
     std::shared_ptr<QPDFObject> getObjectForJSON(int id, int gen);
     void removeObject(QPDFObjGen og);
     void updateCache(
-        QPDFObjGen const& og,
+        QPDFObjGen og,
         std::shared_ptr<QPDFObject> const& object,
         qpdf_offset_t end_before_space,
         qpdf_offset_t end_after_space);
@@ -1100,7 +1100,7 @@ class QPDF
 
     // Calls finish() on the pipeline when done but does not delete it
     bool pipeStreamData(
-        QPDFObjGen const& og,
+        QPDFObjGen og,
         qpdf_offset_t offset,
         size_t length,
         QPDFObjectHandle dict,
@@ -1113,7 +1113,7 @@ class QPDF
         std::shared_ptr<QPDF::EncryptionParameters> encp,
         std::shared_ptr<InputSource> file,
         QPDF& qpdf_for_warning,
-        QPDFObjGen const& og,
+        QPDFObjGen og,
         qpdf_offset_t offset,
         size_t length,
         QPDFObjectHandle dict,
@@ -1174,8 +1174,8 @@ class QPDF
     interpretCF(std::shared_ptr<EncryptionParameters> encp, QPDFObjectHandle);
     void initializeEncryption();
     static std::string
-    getKeyForObject(std::shared_ptr<EncryptionParameters> encp, QPDFObjGen const& og, bool use_aes);
-    void decryptString(std::string&, QPDFObjGen const& og);
+    getKeyForObject(std::shared_ptr<EncryptionParameters> encp, QPDFObjGen og, bool use_aes);
+    void decryptString(std::string&, QPDFObjGen og);
     static std::string
     compute_encryption_key_from_password(std::string const& password, EncryptionData const& data);
     static std::string
@@ -1187,7 +1187,7 @@ class QPDF
         std::shared_ptr<InputSource> file,
         QPDF& qpdf_for_warning,
         Pipeline*& pipeline,
-        QPDFObjGen const& og,
+        QPDFObjGen og,
         QPDFObjectHandle& stream_dict,
         std::unique_ptr<Pipeline>& heap);
 
@@ -1408,7 +1408,7 @@ class QPDF
     void readHSharedObject(BitStream);
     void readHGeneric(BitStream, HGeneric&);
     qpdf_offset_t maxEnd(ObjUser const& ou);
-    qpdf_offset_t getLinearizationOffset(QPDFObjGen const&);
+    qpdf_offset_t getLinearizationOffset(QPDFObjGen);
     QPDFObjectHandle
     getUncompressedObject(QPDFObjectHandle&, std::map<int, int> const& object_stream_data);
     QPDFObjectHandle getUncompressedObject(QPDFObjectHandle&, QPDFWriter::ObjTable const& obj);
diff --git a/include/qpdf/QPDFOutlineDocumentHelper.hh b/include/qpdf/QPDFOutlineDocumentHelper.hh
index c3c3f5e..1f152d5 100644
--- a/include/qpdf/QPDFOutlineDocumentHelper.hh
+++ b/include/qpdf/QPDFOutlineDocumentHelper.hh
@@ -58,16 +58,14 @@ class QPDFOutlineDocumentHelper: public QPDFDocumentHelper
 
     // Return a list outlines that are known to target the specified page.
     QPDF_DLL
-    std::vector<QPDFOutlineObjectHelper> getOutlinesForPage(QPDFObjGen const&);
+    std::vector<QPDFOutlineObjectHelper> getOutlinesForPage(QPDFObjGen);
 
     class Accessor
     {
         friend class QPDFOutlineObjectHelper;
 
-        // ABI: remove  QPDF_DLL and pass og by value.
-        QPDF_DLL
         static bool
-        checkSeen(QPDFOutlineDocumentHelper& dh, QPDFObjGen const& og)
+        checkSeen(QPDFOutlineDocumentHelper& dh, QPDFObjGen og)
         {
             return !dh.m->seen.add(og);
         }
diff --git a/include/qpdf/QPDFWriter.hh b/include/qpdf/QPDFWriter.hh
index 0cde221..6b79a7f 100644
--- a/include/qpdf/QPDFWriter.hh
+++ b/include/qpdf/QPDFWriter.hh
@@ -485,7 +485,7 @@ class QPDFWriter
     void writeStringQDF(std::string_view str);
     void writeStringNoQDF(std::string_view str);
     void writePad(size_t nspaces);
-    void assignCompressedObjectNumbers(QPDFObjGen const& og);
+    void assignCompressedObjectNumbers(QPDFObjGen og);
     void enqueueObject(QPDFObjectHandle object);
     void writeObjectStreamOffsets(std::vector<qpdf_offset_t>& offsets, int first_obj);
     void writeObjectStream(QPDFObjectHandle object);
diff --git a/libqpdf/QPDF.cc b/libqpdf/QPDF.cc
index 70bdf62..60303d1 100644
--- a/libqpdf/QPDF.cc
+++ b/libqpdf/QPDF.cc
@@ -112,7 +112,7 @@ namespace
 QPDF::ForeignStreamData::ForeignStreamData(
     std::shared_ptr<EncryptionParameters> encp,
     std::shared_ptr<InputSource> file,
-    QPDFObjGen const& foreign_og,
+    QPDFObjGen foreign_og,
     qpdf_offset_t offset,
     size_t length,
     QPDFObjectHandle local_dict) :
@@ -164,7 +164,7 @@ QPDF::CopiedStreamDataProvider::registerForeignStream(
     this->foreign_stream_data[local_og] = foreign_stream;
 }
 
-QPDF::StringDecrypter::StringDecrypter(QPDF* qpdf, QPDFObjGen const& og) :
+QPDF::StringDecrypter::StringDecrypter(QPDF* qpdf, QPDFObjGen og) :
     qpdf(qpdf),
     og(og)
 {
@@ -1463,7 +1463,7 @@ QPDF::getAllObjects()
 }
 
 void
-QPDF::setLastObjectDescription(std::string const& description, QPDFObjGen const& og)
+QPDF::setLastObjectDescription(std::string const& description, QPDFObjGen og)
 {
     m->last_object_description.clear();
     if (!description.empty()) {
@@ -1650,7 +1650,7 @@ QPDF::findEndstream()
 
 size_t
 QPDF::recoverStreamLength(
-    std::shared_ptr<InputSource> input, QPDFObjGen const& og, qpdf_offset_t stream_offset)
+    std::shared_ptr<InputSource> input, QPDFObjGen og, qpdf_offset_t stream_offset)
 {
     // Try to reconstruct stream length by looking for endstream or endobj
     warn(damagedPDF(*input, stream_offset, "attempting to recover stream length"));
@@ -2023,7 +2023,7 @@ QPDF::resolveObjectsInStream(int obj_stream_number)
 }
 
 QPDFObjectHandle
-QPDF::newIndirect(QPDFObjGen const& og, std::shared_ptr<QPDFObject> const& obj)
+QPDF::newIndirect(QPDFObjGen og, std::shared_ptr<QPDFObject> const& obj)
 {
     obj->setDefaultDescription(this, og);
     return {obj};
@@ -2031,7 +2031,7 @@ QPDF::newIndirect(QPDFObjGen const& og, std::shared_ptr<QPDFObject> const& obj)
 
 void
 QPDF::updateCache(
-    QPDFObjGen const& og,
+    QPDFObjGen og,
     std::shared_ptr<QPDFObject> const& object,
     qpdf_offset_t end_before_space,
     qpdf_offset_t end_after_space)
@@ -2048,13 +2048,13 @@ QPDF::updateCache(
 }
 
 bool
-QPDF::isCached(QPDFObjGen const& og)
+QPDF::isCached(QPDFObjGen og)
 {
     return m->obj_cache.count(og) != 0;
 }
 
 bool
-QPDF::isUnresolved(QPDFObjGen const& og)
+QPDF::isUnresolved(QPDFObjGen og)
 {
     return !isCached(og) || m->obj_cache[og].object->isUnresolved();
 }
@@ -2152,7 +2152,7 @@ QPDF::getObjectForJSON(int id, int gen)
 }
 
 QPDFObjectHandle
-QPDF::getObject(QPDFObjGen const& og)
+QPDF::getObject(QPDFObjGen og)
 {
     if (auto it = m->obj_cache.find(og); it != m->obj_cache.end()) {
         return {it->second.object};
@@ -2171,7 +2171,7 @@ QPDF::getObject(int objid, int generation)
 }
 
 QPDFObjectHandle
-QPDF::getObjectByObjGen(QPDFObjGen const& og)
+QPDF::getObjectByObjGen(QPDFObjGen og)
 {
     return getObject(og);
 }
@@ -2189,7 +2189,7 @@ QPDF::replaceObject(int objid, int generation, QPDFObjectHandle oh)
 }
 
 void
-QPDF::replaceObject(QPDFObjGen const& og, QPDFObjectHandle oh)
+QPDF::replaceObject(QPDFObjGen og, QPDFObjectHandle oh)
 {
     if (!oh || (oh.isIndirect() && !(oh.isStream() && oh.getObjGen() == og))) {
         QTC::TC("qpdf", "QPDF replaceObject called with indirect object");
@@ -2493,7 +2493,7 @@ QPDF::swapObjects(int objid1, int generation1, int objid2, int generation2)
 }
 
 void
-QPDF::swapObjects(QPDFObjGen const& og1, QPDFObjGen const& og2)
+QPDF::swapObjects(QPDFObjGen og1, QPDFObjGen og2)
 {
     // Force objects to be read from the input source if needed, then swap them in the cache.
     resolve(og1);
@@ -2727,7 +2727,7 @@ QPDF::pipeStreamData(
     std::shared_ptr<EncryptionParameters> encp,
     std::shared_ptr<InputSource> file,
     QPDF& qpdf_for_warning,
-    QPDFObjGen const& og,
+    QPDFObjGen og,
     qpdf_offset_t offset,
     size_t length,
     QPDFObjectHandle stream_dict,
@@ -2789,7 +2789,7 @@ QPDF::pipeStreamData(
 
 bool
 QPDF::pipeStreamData(
-    QPDFObjGen const& og,
+    QPDFObjGen og,
     qpdf_offset_t offset,
     size_t length,
     QPDFObjectHandle stream_dict,
diff --git a/libqpdf/QPDFOutlineDocumentHelper.cc b/libqpdf/QPDFOutlineDocumentHelper.cc
index 51783b1..9028cd3 100644
--- a/libqpdf/QPDFOutlineDocumentHelper.cc
+++ b/libqpdf/QPDFOutlineDocumentHelper.cc
@@ -50,7 +50,7 @@ QPDFOutlineDocumentHelper::initializeByPage()
 }
 
 std::vector<QPDFOutlineObjectHelper>
-QPDFOutlineDocumentHelper::getOutlinesForPage(QPDFObjGen const& og)
+QPDFOutlineDocumentHelper::getOutlinesForPage(QPDFObjGen og)
 {
     if (m->by_page.empty()) {
         initializeByPage();
diff --git a/libqpdf/QPDFWriter.cc b/libqpdf/QPDFWriter.cc
index 6652a40..d0d9159 100644
--- a/libqpdf/QPDFWriter.cc
+++ b/libqpdf/QPDFWriter.cc
@@ -1058,7 +1058,7 @@ QPDFWriter::closeObject(int objid)
 }
 
 void
-QPDFWriter::assignCompressedObjectNumbers(QPDFObjGen const& og)
+QPDFWriter::assignCompressedObjectNumbers(QPDFObjGen og)
 {
     int objid = og.getObj();
     if ((og.getGen() != 0) || (m->object_stream_to_objects.count(objid) == 0)) {
diff --git a/libqpdf/QPDF_Unresolved.cc b/libqpdf/QPDF_Unresolved.cc
index a322e57..ae0c6a6 100644
--- a/libqpdf/QPDF_Unresolved.cc
+++ b/libqpdf/QPDF_Unresolved.cc
@@ -3,13 +3,13 @@
 #include <qpdf/QPDF.hh>
 #include <qpdf/QPDFObject_private.hh>
 
-QPDF_Unresolved::QPDF_Unresolved(QPDF* qpdf, QPDFObjGen const& og) :
+QPDF_Unresolved::QPDF_Unresolved(QPDF* qpdf, QPDFObjGen og) :
     QPDFValue(::ot_unresolved, qpdf, og)
 {
 }
 
 std::shared_ptr<QPDFObject>
-QPDF_Unresolved::create(QPDF* qpdf, QPDFObjGen const& og)
+QPDF_Unresolved::create(QPDF* qpdf, QPDFObjGen og)
 {
     return do_create(new QPDF_Unresolved(qpdf, og));
 }
diff --git a/libqpdf/QPDF_encryption.cc b/libqpdf/QPDF_encryption.cc
index 952b860..9f39345 100644
--- a/libqpdf/QPDF_encryption.cc
+++ b/libqpdf/QPDF_encryption.cc
@@ -952,8 +952,7 @@ QPDF::initializeEncryption()
 }
 
 std::string
-QPDF::getKeyForObject(
-    std::shared_ptr<EncryptionParameters> encp, QPDFObjGen const& og, bool use_aes)
+QPDF::getKeyForObject(std::shared_ptr<EncryptionParameters> encp, QPDFObjGen og, bool use_aes)
 {
     if (!encp->encrypted) {
         throw std::logic_error("request for encryption key in non-encrypted PDF");
@@ -974,7 +973,7 @@ QPDF::getKeyForObject(
 }
 
 void
-QPDF::decryptString(std::string& str, QPDFObjGen const& og)
+QPDF::decryptString(std::string& str, QPDFObjGen og)
 {
     if (!og.isIndirect()) {
         return;
@@ -1048,7 +1047,7 @@ QPDF::decryptStream(
     std::shared_ptr<InputSource> file,
     QPDF& qpdf_for_warning,
     Pipeline*& pipeline,
-    QPDFObjGen const& og,
+    QPDFObjGen og,
     QPDFObjectHandle& stream_dict,
     std::unique_ptr<Pipeline>& decrypt_pipeline)
 {
diff --git a/libqpdf/QPDF_linearization.cc b/libqpdf/QPDF_linearization.cc
index 907734a..703617a 100644
--- a/libqpdf/QPDF_linearization.cc
+++ b/libqpdf/QPDF_linearization.cc
@@ -557,7 +557,7 @@ QPDF::maxEnd(ObjUser const& ou)
 }
 
 qpdf_offset_t
-QPDF::getLinearizationOffset(QPDFObjGen const& og)
+QPDF::getLinearizationOffset(QPDFObjGen og)
 {
     QPDFXRefEntry entry = m->xref_table[og];
     qpdf_offset_t result = 0;
diff --git a/libqpdf/QPDF_pages.cc b/libqpdf/QPDF_pages.cc
index d64b08f..aa90f7f 100644
--- a/libqpdf/QPDF_pages.cc
+++ b/libqpdf/QPDF_pages.cc
@@ -323,7 +323,7 @@ QPDF::findPage(QPDFObjectHandle& page)
 }
 
 int
-QPDF::findPage(QPDFObjGen const& og)
+QPDF::findPage(QPDFObjGen og)
 {
     flattenPagesTree();
     auto it = m->pageobj_to_pages_pos.find(og);
diff --git a/libqpdf/qpdf/QPDFObject_private.hh b/libqpdf/qpdf/QPDFObject_private.hh
index f323d95..d3f3821 100644
--- a/libqpdf/qpdf/QPDFObject_private.hh
+++ b/libqpdf/qpdf/QPDFObject_private.hh
@@ -132,13 +132,13 @@ class QPDFObject
     }
 
     void
-    setDefaultDescription(QPDF* qpdf, QPDFObjGen const& og)
+    setDefaultDescription(QPDF* qpdf, QPDFObjGen og)
     {
         // Intended for use by the QPDF class
         value->setDefaultDescription(qpdf, og);
     }
     void
-    setObjGen(QPDF* qpdf, QPDFObjGen const& og)
+    setObjGen(QPDF* qpdf, QPDFObjGen og)
     {
         value->qpdf = qpdf;
         value->og = og;
diff --git a/libqpdf/qpdf/QPDFValue.hh b/libqpdf/qpdf/QPDFValue.hh
index c2fc748..b247093 100644
--- a/libqpdf/qpdf/QPDFValue.hh
+++ b/libqpdf/qpdf/QPDFValue.hh
@@ -65,7 +65,7 @@ class QPDFValue: public std::enable_shared_from_this<QPDFValue>
         setParsedOffset(offset);
     }
     void
-    setDefaultDescription(QPDF* a_qpdf, QPDFObjGen const& a_og)
+    setDefaultDescription(QPDF* a_qpdf, QPDFObjGen a_og)
     {
         qpdf = a_qpdf;
         og = a_og;
diff --git a/libqpdf/qpdf/QPDF_Unresolved.hh b/libqpdf/qpdf/QPDF_Unresolved.hh
index df443d3..bcd5a63 100644
--- a/libqpdf/qpdf/QPDF_Unresolved.hh
+++ b/libqpdf/qpdf/QPDF_Unresolved.hh
@@ -7,14 +7,14 @@ class QPDF_Unresolved: public QPDFValue
 {
   public:
     ~QPDF_Unresolved() override = default;
-    static std::shared_ptr<QPDFObject> create(QPDF* qpdf, QPDFObjGen const& og);
+    static std::shared_ptr<QPDFObject> create(QPDF* qpdf, QPDFObjGen og);
     std::shared_ptr<QPDFObject> copy(bool shallow = false) override;
     std::string unparse() override;
     void writeJSON(int json_version, JSON::Writer& p) override;
     std::string getStringValue() const override;
 
   private:
-    QPDF_Unresolved(QPDF* qpdf, QPDFObjGen const& og);
+    QPDF_Unresolved(QPDF* qpdf, QPDFObjGen og);
 };
 
 #endif // QPDF_UNRESOLVED_HH