diff --git a/libqpdf/QPDFObject.cc b/libqpdf/QPDFObject.cc
index cffb8a56..ab8f1f62 100644
--- a/libqpdf/QPDFObject.cc
+++ b/libqpdf/QPDFObject.cc
@@ -26,11 +26,11 @@ QPDFObject::getDescription(QPDF*& qpdf, std::string& description)
 {
     qpdf = this->m->owning_qpdf;
     description = this->m->object_description;
-    return this->m->owning_qpdf;
+    return this->m->owning_qpdf != 0;
 }
 
 bool
 QPDFObject::hasDescription()
 {
-    return this->m->owning_qpdf;
+    return this->m->owning_qpdf != 0;
 }
diff --git a/libqpdf/QPDF_encryption.cc b/libqpdf/QPDF_encryption.cc
index c02f1aac..d72d6fb7 100644
--- a/libqpdf/QPDF_encryption.cc
+++ b/libqpdf/QPDF_encryption.cc
@@ -1425,7 +1425,7 @@ static bool
 is_bit_set(int P, int bit)
 {
     // Bits in P are numbered from 1 in the spec
-    return (P & (1 << (bit - 1)));
+    return ((P & (1 << (bit - 1))) != 0);
 }
 
 bool
diff --git a/libqpdf/qpdf-c.cc b/libqpdf/qpdf-c.cc
index 00712a93..f42b0e16 100644
--- a/libqpdf/qpdf-c.cc
+++ b/libqpdf/qpdf-c.cc
@@ -257,19 +257,19 @@ QPDF_ERROR_CODE qpdf_check_pdf(qpdf_data qpdf)
 void qpdf_set_suppress_warnings(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_suppress_warnings");
-    qpdf->qpdf->setSuppressWarnings(value);
+    qpdf->qpdf->setSuppressWarnings(value == QPDF_TRUE);
 }
 
 void qpdf_set_ignore_xref_streams(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_ignore_xref_streams");
-    qpdf->qpdf->setIgnoreXRefStreams(value);
+    qpdf->qpdf->setIgnoreXRefStreams(value == QPDF_TRUE);
 }
 
 void qpdf_set_attempt_recovery(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_attempt_recovery");
-    qpdf->qpdf->setAttemptRecovery(value);
+    qpdf->qpdf->setAttemptRecovery(value == QPDF_TRUE);
 }
 
 QPDF_ERROR_CODE qpdf_read(qpdf_data qpdf, char const* filename,
@@ -398,55 +398,55 @@ QPDF_BOOL qpdf_is_encrypted(qpdf_data qpdf)
 QPDF_BOOL qpdf_allow_accessibility(qpdf_data qpdf)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_allow_accessibility");
-    return qpdf->qpdf->allowAccessibility();
+    return (qpdf->qpdf->allowAccessibility() ? QPDF_TRUE : QPDF_FALSE);
 }
 
 QPDF_BOOL qpdf_allow_extract_all(qpdf_data qpdf)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_allow_extract_all");
-    return qpdf->qpdf->allowExtractAll();
+    return (qpdf->qpdf->allowExtractAll() ? QPDF_TRUE : QPDF_FALSE);
 }
 
 QPDF_BOOL qpdf_allow_print_low_res(qpdf_data qpdf)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_allow_print_low_res");
-    return qpdf->qpdf->allowPrintLowRes();
+    return (qpdf->qpdf->allowPrintLowRes() ? QPDF_TRUE : QPDF_FALSE);
 }
 
 QPDF_BOOL qpdf_allow_print_high_res(qpdf_data qpdf)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_allow_print_high_res");
-    return qpdf->qpdf->allowPrintHighRes();
+    return (qpdf->qpdf->allowPrintHighRes() ? QPDF_TRUE : QPDF_FALSE);
 }
 
 QPDF_BOOL qpdf_allow_modify_assembly(qpdf_data qpdf)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_allow_modify_assembly");
-    return qpdf->qpdf->allowModifyAssembly();
+    return (qpdf->qpdf->allowModifyAssembly() ? QPDF_TRUE : QPDF_FALSE);
 }
 
 QPDF_BOOL qpdf_allow_modify_form(qpdf_data qpdf)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_allow_modify_form");
-    return qpdf->qpdf->allowModifyForm();
+    return (qpdf->qpdf->allowModifyForm() ? QPDF_TRUE : QPDF_FALSE);
 }
 
 QPDF_BOOL qpdf_allow_modify_annotation(qpdf_data qpdf)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_allow_modify_annotation");
-    return qpdf->qpdf->allowModifyAnnotation();
+    return (qpdf->qpdf->allowModifyAnnotation() ? QPDF_TRUE : QPDF_FALSE);
 }
 
 QPDF_BOOL qpdf_allow_modify_other(qpdf_data qpdf)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_allow_modify_other");
-    return qpdf->qpdf->allowModifyOther();
+    return (qpdf->qpdf->allowModifyOther() ? QPDF_TRUE : QPDF_FALSE);
 }
 
 QPDF_BOOL qpdf_allow_modify_all(qpdf_data qpdf)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_allow_modify_all");
-    return qpdf->qpdf->allowModifyAll();
+    return (qpdf->qpdf->allowModifyAll() ? QPDF_TRUE : QPDF_FALSE);
 }
 
 static void qpdf_init_write_internal(qpdf_data qpdf)
@@ -523,7 +523,7 @@ void qpdf_set_object_stream_mode(qpdf_data qpdf, qpdf_object_stream_e mode)
 void qpdf_set_compress_streams(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_compress_streams");
-    qpdf->qpdf_writer->setCompressStreams(value);
+    qpdf->qpdf_writer->setCompressStreams(value == QPDF_TRUE);
 }
 
 void qpdf_set_decode_level(qpdf_data qpdf, qpdf_stream_decode_level_e level)
@@ -535,13 +535,13 @@ void qpdf_set_decode_level(qpdf_data qpdf, qpdf_stream_decode_level_e level)
 void qpdf_set_preserve_unreferenced_objects(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_preserve_unreferenced_objects");
-    qpdf->qpdf_writer->setPreserveUnreferencedObjects(value);
+    qpdf->qpdf_writer->setPreserveUnreferencedObjects(value == QPDF_TRUE);
 }
 
 void qpdf_set_newline_before_endstream(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_newline_before_endstream");
-    qpdf->qpdf_writer->setNewlineBeforeEndstream(value);
+    qpdf->qpdf_writer->setNewlineBeforeEndstream(value == QPDF_TRUE);
 }
 
 void qpdf_set_stream_data_mode(qpdf_data qpdf, qpdf_stream_data_e mode)
@@ -553,44 +553,44 @@ void qpdf_set_stream_data_mode(qpdf_data qpdf, qpdf_stream_data_e mode)
 void qpdf_set_content_normalization(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_content_normalization");
-    qpdf->qpdf_writer->setContentNormalization(value);
+    qpdf->qpdf_writer->setContentNormalization(value == QPDF_TRUE);
 }
 
 void qpdf_set_qdf_mode(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_qdf_mode");
-    qpdf->qpdf_writer->setQDFMode(value);
+    qpdf->qpdf_writer->setQDFMode(value == QPDF_TRUE);
 }
 
 void qpdf_set_deterministic_ID(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_deterministic_ID");
-    qpdf->qpdf_writer->setDeterministicID(value);
+    qpdf->qpdf_writer->setDeterministicID(value == QPDF_TRUE);
 }
 
 void qpdf_set_static_ID(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_static_ID");
-    qpdf->qpdf_writer->setStaticID(value);
+    qpdf->qpdf_writer->setStaticID(value == QPDF_TRUE);
 }
 
 void qpdf_set_static_aes_IV(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_static_aes_IV");
-    qpdf->qpdf_writer->setStaticAesIV(value);
+    qpdf->qpdf_writer->setStaticAesIV(value == QPDF_TRUE);
 }
 
 void qpdf_set_suppress_original_object_IDs(
     qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_suppress_original_object_IDs");
-    qpdf->qpdf_writer->setSuppressOriginalObjectIDs(value);
+    qpdf->qpdf_writer->setSuppressOriginalObjectIDs(value == QPDF_TRUE);
 }
 
 void qpdf_set_preserve_encryption(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_preserve_encryption");
-    qpdf->qpdf_writer->setPreserveEncryption(value);
+    qpdf->qpdf_writer->setPreserveEncryption(value == QPDF_TRUE);
 }
 
 void qpdf_set_r2_encryption_parameters(
@@ -601,7 +601,8 @@ void qpdf_set_r2_encryption_parameters(
     QTC::TC("qpdf", "qpdf-c called qpdf_set_r2_encryption_parameters");
     qpdf->qpdf_writer->setR2EncryptionParameters(
 	user_password, owner_password,
-	allow_print, allow_modify, allow_extract, allow_annotate);
+	allow_print == QPDF_TRUE, allow_modify == QPDF_TRUE,
+        allow_extract == QPDF_TRUE, allow_annotate == QPDF_TRUE);
 }
 
 void qpdf_set_r3_encryption_parameters2(
@@ -614,9 +615,9 @@ void qpdf_set_r3_encryption_parameters2(
     QTC::TC("qpdf", "qpdf-c called qpdf_set_r3_encryption_parameters");
     qpdf->qpdf_writer->setR3EncryptionParameters(
         user_password, owner_password,
-        allow_accessibility, allow_extract,
-        allow_assemble, allow_annotate_and_form,
-        allow_form_filling, allow_modify_other,
+        allow_accessibility == QPDF_TRUE, allow_extract == QPDF_TRUE,
+        allow_assemble == QPDF_TRUE, allow_annotate_and_form == QPDF_TRUE,
+        allow_form_filling == QPDF_TRUE, allow_modify_other == QPDF_TRUE,
         print);
 }
 
@@ -631,10 +632,10 @@ void qpdf_set_r4_encryption_parameters2(
     QTC::TC("qpdf", "qpdf-c called qpdf_set_r4_encryption_parameters");
     qpdf->qpdf_writer->setR4EncryptionParameters(
         user_password, owner_password,
-        allow_accessibility, allow_extract,
-        allow_assemble, allow_annotate_and_form,
-        allow_form_filling, allow_modify_other,
-        print, encrypt_metadata, use_aes);
+        allow_accessibility == QPDF_TRUE, allow_extract == QPDF_TRUE,
+        allow_assemble == QPDF_TRUE, allow_annotate_and_form == QPDF_TRUE,
+        allow_form_filling == QPDF_TRUE, allow_modify_other == QPDF_TRUE,
+        print, encrypt_metadata == QPDF_TRUE, use_aes == QPDF_TRUE);
 }
 
 
@@ -648,10 +649,10 @@ void qpdf_set_r5_encryption_parameters2(
     QTC::TC("qpdf", "qpdf-c called qpdf_set_r5_encryption_parameters");
     qpdf->qpdf_writer->setR5EncryptionParameters(
         user_password, owner_password,
-        allow_accessibility, allow_extract,
-        allow_assemble, allow_annotate_and_form,
-        allow_form_filling, allow_modify_other,
-        print, encrypt_metadata);
+        allow_accessibility == QPDF_TRUE, allow_extract == QPDF_TRUE,
+        allow_assemble == QPDF_TRUE, allow_annotate_and_form == QPDF_TRUE,
+        allow_form_filling == QPDF_TRUE, allow_modify_other == QPDF_TRUE,
+        print, encrypt_metadata == QPDF_TRUE);
 }
 
 void qpdf_set_r6_encryption_parameters2(
@@ -664,10 +665,10 @@ void qpdf_set_r6_encryption_parameters2(
     QTC::TC("qpdf", "qpdf-c called qpdf_set_r6_encryption_parameters");
     qpdf->qpdf_writer->setR6EncryptionParameters(
         user_password, owner_password,
-        allow_accessibility, allow_extract,
-        allow_assemble, allow_annotate_and_form,
-        allow_form_filling, allow_modify_other,
-        print, encrypt_metadata);
+        allow_accessibility == QPDF_TRUE, allow_extract == QPDF_TRUE,
+        allow_assemble == QPDF_TRUE, allow_annotate_and_form == QPDF_TRUE,
+        allow_form_filling == QPDF_TRUE, allow_modify_other == QPDF_TRUE,
+        print, encrypt_metadata == QPDF_TRUE);
 }
 
 void qpdf_set_r3_encryption_parameters(
@@ -677,7 +678,8 @@ void qpdf_set_r3_encryption_parameters(
 {
     qpdf->qpdf_writer->setR3EncryptionParameters(
 	user_password, owner_password,
-	allow_accessibility, allow_extract, print, modify);
+	allow_accessibility == QPDF_TRUE, allow_extract == QPDF_TRUE,
+        print, modify);
 }
 
 void qpdf_set_r4_encryption_parameters(
@@ -688,8 +690,9 @@ void qpdf_set_r4_encryption_parameters(
 {
     qpdf->qpdf_writer->setR4EncryptionParameters(
 	user_password, owner_password,
-	allow_accessibility, allow_extract, print, modify,
-	encrypt_metadata, use_aes);
+	allow_accessibility == QPDF_TRUE, allow_extract == QPDF_TRUE,
+        print, modify,
+	encrypt_metadata == QPDF_TRUE, use_aes == QPDF_TRUE);
 }
 
 void qpdf_set_r5_encryption_parameters(
@@ -700,8 +703,9 @@ void qpdf_set_r5_encryption_parameters(
 {
     qpdf->qpdf_writer->setR5EncryptionParameters(
 	user_password, owner_password,
-	allow_accessibility, allow_extract, print, modify,
-	encrypt_metadata);
+	allow_accessibility == QPDF_TRUE, allow_extract == QPDF_TRUE,
+        print, modify,
+	encrypt_metadata == QPDF_TRUE);
 }
 
 void qpdf_set_r6_encryption_parameters(
@@ -712,14 +716,14 @@ void qpdf_set_r6_encryption_parameters(
 {
     qpdf->qpdf_writer->setR6EncryptionParameters(
 	user_password, owner_password,
-	allow_accessibility, allow_extract, print, modify,
-	encrypt_metadata);
+	allow_accessibility == QPDF_TRUE, allow_extract == QPDF_TRUE,
+        print, modify, encrypt_metadata == QPDF_TRUE);
 }
 
 void qpdf_set_linearization(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_linearization");
-    qpdf->qpdf_writer->setLinearization(value);
+    qpdf->qpdf_writer->setLinearization(value == QPDF_TRUE);
 }
 
 void qpdf_set_minimum_pdf_version(qpdf_data qpdf, char const* version)