diff --git a/lib/add-message.cc b/lib/add-message.cc
index 73bde7fa..bce10a0f 100644
--- a/lib/add-message.cc
+++ b/lib/add-message.cc
@@ -404,7 +404,7 @@ static notmuch_status_t
 _notmuch_database_link_message (notmuch_database_t *notmuch,
 				notmuch_message_t *message,
 				notmuch_message_file_t *message_file,
-				notmuch_bool_t is_ghost)
+				bool is_ghost)
 {
     void *local = talloc_new (NULL);
     notmuch_status_t status;
@@ -467,7 +467,7 @@ notmuch_database_index_file (notmuch_database_t *notmuch,
     notmuch_message_t *message = NULL;
     notmuch_status_t ret = NOTMUCH_STATUS_SUCCESS, ret2;
     notmuch_private_status_t private_status;
-    notmuch_bool_t is_ghost = FALSE, is_new = FALSE;
+    bool is_ghost = false, is_new = false;
 
     const char *date;
     const char *from, *to, *subject;
@@ -510,12 +510,12 @@ notmuch_database_index_file (notmuch_database_t *notmuch,
 	/* We cannot call notmuch_message_get_flag for a new message */
 	switch (private_status) {
 	case NOTMUCH_PRIVATE_STATUS_NO_DOCUMENT_FOUND:
-	    is_ghost = FALSE;
-	    is_new = TRUE;
+	    is_ghost = false;
+	    is_new = true;
 	    break;
 	case NOTMUCH_PRIVATE_STATUS_SUCCESS:
 	    is_ghost = notmuch_message_get_flag (message, NOTMUCH_MESSAGE_FLAG_GHOST);
-	    is_new = FALSE;
+	    is_new = false;
 	    break;
 	default:
 	    ret = COERCE_STATUS (private_status,
@@ -551,7 +551,7 @@ notmuch_database_index_file (notmuch_database_t *notmuch,
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log (notmuch, "A Xapian exception occurred adding message: %s.\n",
 		 error.get_msg().c_str());
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	ret = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 	goto DONE;
     }
diff --git a/lib/built-with.c b/lib/built-with.c
index 2f1f0b5c..27384bd0 100644
--- a/lib/built-with.c
+++ b/lib/built-with.c
@@ -31,6 +31,6 @@ notmuch_built_with (const char *name)
     } else if (STRNCMP_LITERAL (name, "retry_lock") == 0) {
 	return HAVE_XAPIAN_DB_RETRY_LOCK;
     } else {
-	return FALSE;
+	return false;
     }
 }
diff --git a/lib/config.cc b/lib/config.cc
index 0703b9bb..da71c16e 100644
--- a/lib/config.cc
+++ b/lib/config.cc
@@ -56,7 +56,7 @@ notmuch_database_set_config (notmuch_database_t *notmuch,
 	db->set_metadata (CONFIG_PREFIX + key, value);
     } catch (const Xapian::Error &error) {
 	status = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	_notmuch_database_log (notmuch, "Error: A Xapian exception occurred setting metadata: %s\n",
 			       error.get_msg().c_str());
     }
@@ -74,7 +74,7 @@ _metadata_value (notmuch_database_t *notmuch,
 	value = notmuch->xapian_db->get_metadata (CONFIG_PREFIX + key);
     } catch (const Xapian::Error &error) {
 	status = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	_notmuch_database_log (notmuch, "Error: A Xapian exception occurred getting metadata: %s\n",
 			       error.get_msg().c_str());
     }
@@ -128,7 +128,7 @@ notmuch_database_get_config_list (notmuch_database_t *notmuch,
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log (notmuch, "A Xapian exception occurred getting metadata iterator: %s.\n",
 			       error.get_msg().c_str());
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	status = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
 
@@ -145,9 +145,9 @@ notmuch_bool_t
 notmuch_config_list_valid (notmuch_config_list_t *metadata)
 {
     if (metadata->iterator == metadata->notmuch->xapian_db->metadata_keys_end ())
-	return FALSE;
+	return false;
 
-    return TRUE;
+    return true;
 }
 
 const char *
diff --git a/lib/database-private.h b/lib/database-private.h
index 5555554b..a499b259 100644
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -179,14 +179,14 @@ operator&(notmuch_field_flag_t a, notmuch_field_flag_t b)
 				    Xapian::QueryParser::FLAG_PURE_NOT)
 
 struct _notmuch_database {
-    notmuch_bool_t exception_reported;
+    bool exception_reported;
 
     char *path;
 
     notmuch_database_mode_t mode;
     int atomic_nesting;
-    /* TRUE if changes have been made in this atomic section */
-    notmuch_bool_t atomic_dirty;
+    /* true if changes have been made in this atomic section */
+    bool atomic_dirty;
     Xapian::Database *xapian_db;
 
     /* Bit mask of features used by this database.  This is a
diff --git a/lib/database.cc b/lib/database.cc
index 79eb3d69..35c66939 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -562,7 +562,7 @@ notmuch_database_find_message (notmuch_database_t *notmuch,
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log (notmuch, "A Xapian exception occurred finding message: %s.\n",
 		 error.get_msg().c_str());
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	*message_ret = NULL;
 	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
@@ -691,7 +691,7 @@ _notmuch_database_new_revision (notmuch_database_t *notmuch)
      * committed revision number until we commit the atomic section.
      */
     if (notmuch->atomic_nesting)
-	notmuch->atomic_dirty = TRUE;
+	notmuch->atomic_dirty = true;
     else
 	notmuch->revision = new_revision;
 
@@ -854,7 +854,7 @@ notmuch_database_open_verbose (const char *path,
     }
 
     notmuch = talloc_zero (NULL, notmuch_database_t);
-    notmuch->exception_reported = FALSE;
+    notmuch->exception_reported = false;
     notmuch->status_string = NULL;
     notmuch->path = talloc_strdup (notmuch, path);
 
@@ -1040,7 +1040,7 @@ _notmuch_database_reopen (notmuch_database_t *notmuch)
 	if (! notmuch->exception_reported) {
 	    _notmuch_database_log (notmuch, "Error: A Xapian exception reopening database: %s\n",
 				   error.get_msg ().c_str ());
-	    notmuch->exception_reported = TRUE;
+	    notmuch->exception_reported = true;
 	}
 	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
@@ -1118,7 +1118,7 @@ notmuch_database_compact (const char *path,
     notmuch_status_t ret = NOTMUCH_STATUS_SUCCESS;
     notmuch_database_t *notmuch = NULL;
     struct stat statbuf;
-    notmuch_bool_t keep_backup;
+    bool keep_backup;
     char *message = NULL;
 
     local = talloc_new (NULL);
@@ -1154,10 +1154,10 @@ notmuch_database_compact (const char *path,
 	    ret = NOTMUCH_STATUS_OUT_OF_MEMORY;
 	    goto DONE;
 	}
-	keep_backup = FALSE;
+	keep_backup = false;
     }
     else {
-	keep_backup = TRUE;
+	keep_backup = true;
     }
 
     if (stat (backup_path, &statbuf) != -1) {
@@ -1313,7 +1313,7 @@ notmuch_database_upgrade (notmuch_database_t *notmuch,
     Xapian::WritableDatabase *db;
     struct sigaction action;
     struct itimerval timerval;
-    notmuch_bool_t timer_is_active = FALSE;
+    bool timer_is_active = false;
     enum _notmuch_features target_features, new_features;
     notmuch_status_t status;
     notmuch_private_status_t private_status;
@@ -1347,7 +1347,7 @@ notmuch_database_upgrade (notmuch_database_t *notmuch,
 	timerval.it_value.tv_usec = 0;
 	setitimer (ITIMER_REAL, &timerval, NULL);
 
-	timer_is_active = TRUE;
+	timer_is_active = true;
     }
 
     /* Figure out how much total work we need to do. */
@@ -1588,7 +1588,7 @@ notmuch_database_begin_atomic (notmuch_database_t *notmuch)
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log (notmuch, "A Xapian exception occurred beginning transaction: %s.\n",
 		 error.get_msg().c_str());
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
 
@@ -1622,13 +1622,13 @@ notmuch_database_end_atomic (notmuch_database_t *notmuch)
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log (notmuch, "A Xapian exception occurred committing transaction: %s.\n",
 		 error.get_msg().c_str());
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
 
     if (notmuch->atomic_dirty) {
 	++notmuch->revision;
-	notmuch->atomic_dirty = FALSE;
+	notmuch->atomic_dirty = false;
     }
 
 DONE:
@@ -1871,7 +1871,7 @@ notmuch_database_get_directory (notmuch_database_t *notmuch,
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log (notmuch, "A Xapian exception occurred getting directory: %s.\n",
 		 error.get_msg().c_str());
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	status = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
     return status;
@@ -1968,7 +1968,7 @@ notmuch_database_find_message_by_filename (notmuch_database_t *notmuch,
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log (notmuch, "Error: A Xapian exception occurred finding message by filename: %s\n",
 		 error.get_msg().c_str());
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	status = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
 
@@ -2021,7 +2021,7 @@ notmuch_database_get_all_tags (notmuch_database_t *db)
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log (db, "A Xapian exception occurred getting tags: %s.\n",
 		 error.get_msg().c_str());
-	db->exception_reported = TRUE;
+	db->exception_reported = true;
 	return NULL;
     }
 }
diff --git a/lib/directory.cc b/lib/directory.cc
index 5de3319c..4fcb0177 100644
--- a/lib/directory.cc
+++ b/lib/directory.cc
@@ -103,7 +103,7 @@ _notmuch_directory_create (notmuch_database_t *notmuch,
     notmuch_directory_t *directory;
     notmuch_private_status_t private_status;
     const char *db_path;
-    notmuch_bool_t create = (flags & NOTMUCH_FIND_CREATE);
+    bool create = (flags & NOTMUCH_FIND_CREATE);
 
     if (! (notmuch->features & NOTMUCH_FEATURE_DIRECTORY_DOCS)) {
 	*status_ret = NOTMUCH_STATUS_UPGRADE_REQUIRED;
@@ -189,7 +189,7 @@ _notmuch_directory_create (notmuch_database_t *notmuch,
 	_notmuch_database_log (notmuch,
 		 "A Xapian exception occurred creating a directory: %s.\n",
 		 error.get_msg().c_str());
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	notmuch_directory_destroy (directory);
 	directory = NULL;
 	*status_ret = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
@@ -234,7 +234,7 @@ notmuch_directory_set_mtime (notmuch_directory_t *directory,
 	_notmuch_database_log (notmuch,
 		 "A Xapian exception occurred setting directory mtime: %s.\n",
 		 error.get_msg().c_str());
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
 
@@ -301,7 +301,7 @@ notmuch_directory_delete (notmuch_directory_t *directory)
 	_notmuch_database_log (directory->notmuch,
 			       "A Xapian exception occurred deleting directory entry: %s.\n",
 			       error.get_msg().c_str());
-	directory->notmuch->exception_reported = TRUE;
+	directory->notmuch->exception_reported = true;
 	status = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
     notmuch_directory_destroy (directory);
diff --git a/lib/filenames.c b/lib/filenames.c
index 63e737dd..37d631d6 100644
--- a/lib/filenames.c
+++ b/lib/filenames.c
@@ -46,7 +46,7 @@ notmuch_bool_t
 notmuch_filenames_valid (notmuch_filenames_t *filenames)
 {
     if (filenames == NULL)
-	return FALSE;
+	return false;
 
     return (filenames->iterator != NULL);
 }
diff --git a/lib/index.cc b/lib/index.cc
index ceb444df..e5ae2ba7 100644
--- a/lib/index.cc
+++ b/lib/index.cc
@@ -184,7 +184,7 @@ filter_filter (GMimeFilter *gmime_filter, char *inbuf, size_t inlen, size_t pres
 
     int next;
 
-    g_mime_filter_set_size (gmime_filter, inlen, FALSE);
+    g_mime_filter_set_size (gmime_filter, inlen, false);
     outptr = gmime_filter->outbuf;
 
     next = filter->state;
@@ -460,7 +460,7 @@ _index_mime_part (notmuch_message_t *message,
     byte_array = g_byte_array_new ();
 
     stream = g_mime_stream_mem_new_with_byte_array (byte_array);
-    g_mime_stream_mem_set_owner (GMIME_STREAM_MEM (stream), FALSE);
+    g_mime_stream_mem_set_owner (GMIME_STREAM_MEM (stream), false);
 
     filter = g_mime_stream_filter_new (stream);
 
@@ -493,7 +493,7 @@ _index_mime_part (notmuch_message_t *message,
     g_object_unref (discard_non_term_filter);
 
     g_byte_array_append (byte_array, (guint8 *) "\0", 1);
-    body = (char *) g_byte_array_free (byte_array, FALSE);
+    body = (char *) g_byte_array_free (byte_array, false);
 
     if (body) {
 	_notmuch_message_gen_terms (message, NULL, body);
diff --git a/lib/message-file.c b/lib/message-file.c
index b90df305..8f0dbbda 100644
--- a/lib/message-file.c
+++ b/lib/message-file.c
@@ -104,16 +104,16 @@ _notmuch_message_file_close (notmuch_message_file_t *message)
     talloc_free (message);
 }
 
-static notmuch_bool_t
+static bool
 _is_mbox (FILE *file)
 {
     char from_buf[5];
-    notmuch_bool_t ret = FALSE;
+    bool ret = false;
 
     /* Is this mbox? */
     if (fread (from_buf, sizeof (from_buf), 1, file) == 1 &&
 	strncmp (from_buf, "From ", 5) == 0)
-	ret = TRUE;
+	ret = true;
 
     rewind (file);
 
@@ -127,7 +127,7 @@ _notmuch_message_file_parse (notmuch_message_file_t *message)
     GMimeParser *parser;
     notmuch_status_t status = NOTMUCH_STATUS_SUCCESS;
     static int initialized = 0;
-    notmuch_bool_t is_mbox;
+    bool is_mbox;
 
     if (message->message)
 	return NOTMUCH_STATUS_SUCCESS;
@@ -147,7 +147,7 @@ _notmuch_message_file_parse (notmuch_message_file_t *message)
     stream = g_mime_stream_file_new (message->file);
 
     /* We'll own and fclose the FILE* ourselves. */
-    g_mime_stream_file_set_owner (GMIME_STREAM_FILE (stream), FALSE);
+    g_mime_stream_file_set_owner (GMIME_STREAM_FILE (stream), false);
 
     parser = g_mime_parser_new_with_stream (stream);
     g_mime_parser_set_scan_from (parser, is_mbox);
diff --git a/lib/message-private.h b/lib/message-private.h
index 74199256..73b080e4 100644
--- a/lib/message-private.h
+++ b/lib/message-private.h
@@ -4,7 +4,7 @@
 notmuch_string_map_t *
 _notmuch_message_property_map (notmuch_message_t *message);
 
-notmuch_bool_t
+bool
 _notmuch_message_frozen (notmuch_message_t *message);
 
 void
diff --git a/lib/message-property.cc b/lib/message-property.cc
index f32d5550..d72c74c3 100644
--- a/lib/message-property.cc
+++ b/lib/message-property.cc
@@ -38,7 +38,7 @@ notmuch_message_get_property (notmuch_message_t *message, const char *key, const
 
 static notmuch_status_t
 _notmuch_message_modify_property (notmuch_message_t *message, const char *key, const char *value,
-				  notmuch_bool_t delete_it)
+				  bool delete_it)
 {
     notmuch_private_status_t private_status;
     notmuch_status_t status;
@@ -76,13 +76,13 @@ _notmuch_message_modify_property (notmuch_message_t *message, const char *key, c
 notmuch_status_t
 notmuch_message_add_property (notmuch_message_t *message, const char *key, const char *value)
 {
-    return _notmuch_message_modify_property (message, key, value, FALSE);
+    return _notmuch_message_modify_property (message, key, value, false);
 }
 
 notmuch_status_t
 notmuch_message_remove_property (notmuch_message_t *message, const char *key, const char *value)
 {
-    return _notmuch_message_modify_property (message, key, value, TRUE);
+    return _notmuch_message_modify_property (message, key, value, true);
 }
 
 notmuch_status_t
diff --git a/lib/message.cc b/lib/message.cc
index 0e3b5a4f..4ab0ed26 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -48,7 +48,7 @@ struct _notmuch_message {
     unsigned long lazy_flags;
 
     /* Message document modified since last sync */
-    notmuch_bool_t modified;
+    bool modified;
 
     /* last view of database the struct is synced with */
     unsigned long last_view;
@@ -62,16 +62,16 @@ struct _notmuch_message {
 struct maildir_flag_tag {
     char flag;
     const char *tag;
-    notmuch_bool_t inverse;
+    bool inverse;
 };
 
 /* ASCII ordered table of Maildir flags and associated tags */
 static struct maildir_flag_tag flag2tag[] = {
-    { 'D', "draft",   FALSE},
-    { 'F', "flagged", FALSE},
-    { 'P', "passed",  FALSE},
-    { 'R', "replied", FALSE},
-    { 'S', "unread",  TRUE }
+    { 'D', "draft",   false},
+    { 'F', "flagged", false},
+    { 'P', "passed",  false},
+    { 'R', "replied", false},
+    { 'S', "unread",  true }
 };
 
 /* We end up having to call the destructor explicitly because we had
@@ -270,7 +270,7 @@ _notmuch_message_create_for_message_id (notmuch_database_t *notmuch,
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log(_notmuch_message_database (message), "A Xapian exception occurred creating message: %s\n",
 		 error.get_msg().c_str());
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	*status_ret = NOTMUCH_PRIVATE_STATUS_XAPIAN_EXCEPTION;
 	return NULL;
     }
@@ -527,7 +527,7 @@ notmuch_message_get_header (notmuch_message_t *message, const char *header)
 	} catch (Xapian::Error &error) {
 	    _notmuch_database_log(_notmuch_message_database (message), "A Xapian exception occurred when reading header: %s\n",
 		     error.get_msg().c_str());
-	    message->notmuch->exception_reported = TRUE;
+	    message->notmuch->exception_reported = true;
 	    return NULL;
 	}
     }
@@ -596,7 +596,7 @@ _notmuch_message_remove_terms (notmuch_message_t *message, const char *prefix)
 
 	try {
 	    message->doc.remove_term ((*i));
-	    message->modified = TRUE;
+	    message->modified = true;
 	} catch (const Xapian::InvalidArgumentError) {
 	    /* Ignore failure to remove non-existent term. */
 	}
@@ -639,7 +639,7 @@ _notmuch_message_remove_indexed_terms (notmuch_message_t *message)
 
 	try {
 	    message->doc.remove_term ((*i));
-	    message->modified = TRUE;
+	    message->modified = true;
 	} catch (const Xapian::InvalidArgumentError) {
 	    /* Ignore failure to remove non-existent term. */
 	} catch (const Xapian::Error &error) {
@@ -648,7 +648,7 @@ _notmuch_message_remove_indexed_terms (notmuch_message_t *message)
 	    if (!notmuch->exception_reported) {
 		_notmuch_database_log(_notmuch_message_database (message), "A Xapian exception occurred creating message: %s\n",
 				      error.get_msg().c_str());
-		notmuch->exception_reported = TRUE;
+		notmuch->exception_reported = true;
 	    }
 	    return NOTMUCH_PRIVATE_STATUS_XAPIAN_EXCEPTION;
 	}
@@ -703,7 +703,7 @@ _notmuch_message_add_folder_terms (notmuch_message_t *message,
 
     talloc_free (folder);
 
-    message->modified = TRUE;
+    message->modified = true;
     return NOTMUCH_STATUS_SUCCESS;
 }
 
@@ -905,7 +905,7 @@ void
 _notmuch_message_clear_data (notmuch_message_t *message)
 {
     message->doc.set_data ("");
-    message->modified = TRUE;
+    message->modified = true;
 }
 
 static void
@@ -1044,7 +1044,7 @@ notmuch_message_get_date (notmuch_message_t *message)
     } catch (Xapian::Error &error) {
 	_notmuch_database_log(_notmuch_message_database (message), "A Xapian exception occurred when reading date: %s\n",
 		 error.get_msg().c_str());
-	message->notmuch->exception_reported = TRUE;
+	message->notmuch->exception_reported = true;
 	return 0;
     }
 
@@ -1115,7 +1115,7 @@ _notmuch_message_set_header_values (notmuch_message_t *message,
 			    Xapian::sortable_serialise (time_value));
     message->doc.add_value (NOTMUCH_VALUE_FROM, from);
     message->doc.add_value (NOTMUCH_VALUE_SUBJECT, subject);
-    message->modified = TRUE;
+    message->modified = true;
 }
 
 /* Upgrade a message to support NOTMUCH_FEATURE_LAST_MOD.  The caller
@@ -1125,7 +1125,7 @@ _notmuch_message_upgrade_last_mod (notmuch_message_t *message)
 {
     /* _notmuch_message_sync will update the last modification
      * revision; we just have to ask it to. */
-    message->modified = TRUE;
+    message->modified = true;
 }
 
 /* Synchronize changes made to message->doc out into the database. */
@@ -1154,7 +1154,7 @@ _notmuch_message_sync (notmuch_message_t *message)
 
     db = static_cast <Xapian::WritableDatabase *> (message->notmuch->xapian_db);
     db->replace_document (message->doc_id, message->doc);
-    message->modified = FALSE;
+    message->modified = false;
 }
 
 /* Delete a message document from the database, leaving a ghost
@@ -1170,7 +1170,7 @@ _notmuch_message_delete (notmuch_message_t *message)
     notmuch_database_t *notmuch;
     notmuch_query_t *query;
     unsigned int count = 0;
-    notmuch_bool_t is_ghost;
+    bool is_ghost;
 
     mid = notmuch_message_get_message_id (message);
     tid = notmuch_message_get_thread_id (message);
@@ -1299,7 +1299,7 @@ _notmuch_message_add_term (notmuch_message_t *message,
 	return NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG;
 
     message->doc.add_term (term, 0);
-    message->modified = TRUE;
+    message->modified = true;
 
     talloc_free (term);
 
@@ -1368,7 +1368,7 @@ _notmuch_message_remove_term (notmuch_message_t *message,
 
     try {
 	message->doc.remove_term (term);
-	message->modified = TRUE;
+	message->modified = true;
     } catch (const Xapian::InvalidArgumentError) {
 	/* We'll let the philosophers try to wrestle with the
 	 * question of whether failing to remove that which was not
@@ -1387,10 +1387,10 @@ notmuch_private_status_t
 _notmuch_message_has_term (notmuch_message_t *message,
 			   const char *prefix_name,
 			   const char *value,
-			   notmuch_bool_t *result)
+			   bool *result)
 {
     char *term;
-    notmuch_bool_t out = FALSE;
+    bool out = false;
     notmuch_private_status_t status = NOTMUCH_PRIVATE_STATUS_SUCCESS;
 
     if (value == NULL)
@@ -1408,7 +1408,7 @@ _notmuch_message_has_term (notmuch_message_t *message,
 	i.skip_to (term);
 	if (i != message->doc.termlist_end () &&
 	    !strcmp ((*i).c_str (), term))
-	    out = TRUE;
+	    out = true;
     } catch (Xapian::Error &error) {
 	status = NOTMUCH_PRIVATE_STATUS_XAPIAN_EXCEPTION;
     }
@@ -1516,7 +1516,7 @@ _filename_is_in_maildir (const char *filename)
 }
 
 static void
-_ensure_maildir_flags (notmuch_message_t *message, notmuch_bool_t force)
+_ensure_maildir_flags (notmuch_message_t *message, bool force)
 {
     const char *flags;
     notmuch_filenames_t *filenames;
@@ -1563,7 +1563,7 @@ _ensure_maildir_flags (notmuch_message_t *message, notmuch_bool_t force)
 notmuch_bool_t
 notmuch_message_has_maildir_flag (notmuch_message_t *message, char flag)
 {
-    _ensure_maildir_flags (message, FALSE);
+    _ensure_maildir_flags (message, false);
     return message->maildir_flags && (strchr (message->maildir_flags, flag) != NULL);
 }
 
@@ -1573,7 +1573,7 @@ notmuch_message_maildir_flags_to_tags (notmuch_message_t *message)
     notmuch_status_t status;
     unsigned i;
 
-    _ensure_maildir_flags (message, TRUE);
+    _ensure_maildir_flags (message, true);
     /* If none of the filenames have any maildir info field (not even
      * an empty info with no flags set) then there's no information to
      * go on, so do nothing. */
@@ -1685,7 +1685,7 @@ _new_maildir_filename (void *ctx,
     char *filename_new, *dir;
     char flag_map[128];
     int flags_in_map = 0;
-    notmuch_bool_t flags_changed = FALSE;
+    bool flags_changed = false;
     unsigned int i;
     char *s;
 
@@ -1726,7 +1726,7 @@ _new_maildir_filename (void *ctx,
 	if (flag_map[flag] == 0) {
 	    flag_map[flag] = 1;
 	    flags_in_map++;
-	    flags_changed = TRUE;
+	    flags_changed = true;
 	}
     }
 
@@ -1735,7 +1735,7 @@ _new_maildir_filename (void *ctx,
 	if (flag_map[flag]) {
 	    flag_map[flag] = 0;
 	    flags_in_map--;
-	    flags_changed = TRUE;
+	    flags_changed = true;
 	}
     }
 
@@ -1953,7 +1953,7 @@ _notmuch_message_property_map (notmuch_message_t *message)
     return message->property_map;
 }
 
-notmuch_bool_t
+bool
 _notmuch_message_frozen (notmuch_message_t *message)
 {
     return message->frozen;
diff --git a/lib/messages.c b/lib/messages.c
index b5363bb8..a88f974f 100644
--- a/lib/messages.c
+++ b/lib/messages.c
@@ -68,7 +68,7 @@ _notmuch_messages_create (notmuch_message_list_t *list)
     if (unlikely (messages == NULL))
 	return NULL;
 
-    messages->is_of_list_type = TRUE;
+    messages->is_of_list_type = true;
     messages->iterator = list->head;
 
     return messages;
@@ -93,7 +93,7 @@ notmuch_bool_t
 notmuch_messages_valid (notmuch_messages_t *messages)
 {
     if (messages == NULL)
-	return FALSE;
+	return false;
 
     if (! messages->is_of_list_type)
 	return _notmuch_mset_messages_valid (messages);
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index b187a80f..e86f4582 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -24,6 +24,7 @@
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE /* For getline and asprintf */
 #endif
+#include <stdbool.h>
 #include <stdio.h>
 
 #include "compat.h"
@@ -282,7 +283,7 @@ notmuch_private_status_t
 _notmuch_message_has_term (notmuch_message_t *message,
 			   const char *prefix_name,
 			   const char *value,
-			   notmuch_bool_t *result);
+			   bool *result);
 
 notmuch_private_status_t
 _notmuch_message_gen_terms (notmuch_message_t *message,
@@ -465,7 +466,7 @@ typedef struct _notmuch_message_list {
  * ignorance of that here. (See notmuch_mset_messages_t in query.cc)
  */
 struct _notmuch_messages {
-    notmuch_bool_t is_of_list_type;
+    bool is_of_list_type;
     notmuch_doc_id_set_t *excluded_doc_ids;
     notmuch_message_node_t *iterator;
 };
@@ -482,7 +483,7 @@ _notmuch_messages_create (notmuch_message_list_t *list);
 
 /* query.cc */
 
-notmuch_bool_t
+bool
 _notmuch_mset_messages_valid (notmuch_messages_t *messages);
 
 notmuch_message_t *
@@ -491,7 +492,7 @@ _notmuch_mset_messages_get (notmuch_messages_t *messages);
 void
 _notmuch_mset_messages_move_to_next (notmuch_messages_t *messages);
 
-notmuch_bool_t
+bool
 _notmuch_doc_id_set_contains (notmuch_doc_id_set_t *doc_ids,
 			      unsigned int doc_id);
 
@@ -591,9 +592,9 @@ _notmuch_string_map_get (notmuch_string_map_t *map, const char *key);
 
 notmuch_string_map_iterator_t *
 _notmuch_string_map_iterator_create (notmuch_string_map_t *map, const char *key,
-				     notmuch_bool_t exact);
+				     bool exact);
 
-notmuch_bool_t
+bool
 _notmuch_string_map_iterator_valid (notmuch_string_map_iterator_t *iter);
 
 void
diff --git a/lib/query.cc b/lib/query.cc
index 9c6ecc8d..d633fa3d 100644
--- a/lib/query.cc
+++ b/lib/query.cc
@@ -29,7 +29,7 @@ struct _notmuch_query {
     notmuch_sort_t sort;
     notmuch_string_list_t *exclude_terms;
     notmuch_exclude_t omit_excluded;
-    notmuch_bool_t parsed;
+    bool parsed;
     Xapian::Query xapian_query;
     std::set<std::string> terms;
 };
@@ -62,12 +62,12 @@ struct _notmuch_threads {
 };
 
 /* We need this in the message functions so forward declare. */
-static notmuch_bool_t
+static bool
 _notmuch_doc_id_set_init (void *ctx,
 			  notmuch_doc_id_set_t *doc_ids,
 			  GArray *arr);
 
-static notmuch_bool_t
+static bool
 _debug_query (void)
 {
     char *env = getenv ("NOTMUCH_DEBUG_QUERY");
@@ -97,7 +97,7 @@ notmuch_query_create (notmuch_database_t *notmuch,
 
     new (&query->xapian_query) Xapian::Query ();
     new (&query->terms) std::set<std::string> ();
-    query->parsed = FALSE;
+    query->parsed = false;
 
     talloc_set_destructor (query, _notmuch_query_destructor);
 
@@ -134,7 +134,7 @@ _notmuch_query_ensure_parsed (notmuch_query_t *query)
 	     t != query->xapian_query.get_terms_end (); ++t)
 	    query->terms.insert (*t);
 
-	query->parsed = TRUE;
+	query->parsed = true;
 
     } catch (const Xapian::Error &error) {
 	if (!query->notmuch->exception_reported) {
@@ -144,7 +144,7 @@ _notmuch_query_ensure_parsed (notmuch_query_t *query)
 	    _notmuch_database_log_append (query->notmuch,
 					  "Query string was: %s\n",
 					  query->query_string);
-	    query->notmuch->exception_reported = TRUE;
+	    query->notmuch->exception_reported = true;
 	}
 
 	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
@@ -261,7 +261,7 @@ _notmuch_query_search_documents (notmuch_query_t *query,
 
     try {
 
-	messages->base.is_of_list_type = FALSE;
+	messages->base.is_of_list_type = false;
 	messages->base.iterator = NULL;
 	messages->notmuch = notmuch;
 	new (&messages->iterator) Xapian::MSetIterator ();
@@ -304,7 +304,7 @@ _notmuch_query_search_documents (notmuch_query_t *query,
 
 		mset = enquire.get_mset (0, notmuch->xapian_db->get_doccount ());
 
-		GArray *excluded_doc_ids = g_array_new (FALSE, FALSE, sizeof (unsigned int));
+		GArray *excluded_doc_ids = g_array_new (false, false, sizeof (unsigned int));
 
 		for (iterator = mset.begin (); iterator != mset.end (); iterator++) {
 		    unsigned int doc_id = *iterator;
@@ -322,13 +322,13 @@ _notmuch_query_search_documents (notmuch_query_t *query,
 
 	switch (query->sort) {
 	case NOTMUCH_SORT_OLDEST_FIRST:
-	    enquire.set_sort_by_value (NOTMUCH_VALUE_TIMESTAMP, FALSE);
+	    enquire.set_sort_by_value (NOTMUCH_VALUE_TIMESTAMP, false);
 	    break;
 	case NOTMUCH_SORT_NEWEST_FIRST:
-	    enquire.set_sort_by_value (NOTMUCH_VALUE_TIMESTAMP, TRUE);
+	    enquire.set_sort_by_value (NOTMUCH_VALUE_TIMESTAMP, true);
 	    break;
 	case NOTMUCH_SORT_MESSAGE_ID:
-	    enquire.set_sort_by_value (NOTMUCH_VALUE_MESSAGE_ID, FALSE);
+	    enquire.set_sort_by_value (NOTMUCH_VALUE_MESSAGE_ID, false);
 	    break;
 	case NOTMUCH_SORT_UNSORTED:
 	    break;
@@ -359,13 +359,13 @@ _notmuch_query_search_documents (notmuch_query_t *query,
 			       "Query string was: %s\n",
 			       query->query_string);
 
-	notmuch->exception_reported = TRUE;
+	notmuch->exception_reported = true;
 	talloc_free (messages);
 	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
 }
 
-notmuch_bool_t
+bool
 _notmuch_mset_messages_valid (notmuch_messages_t *messages)
 {
     notmuch_mset_messages_t *mset_messages;
@@ -415,7 +415,7 @@ _notmuch_mset_messages_get (notmuch_messages_t *messages)
 
     if (messages->excluded_doc_ids &&
 	_notmuch_doc_id_set_contains (messages->excluded_doc_ids, doc_id))
-	notmuch_message_set_flag (message, NOTMUCH_MESSAGE_FLAG_EXCLUDED, TRUE);
+	notmuch_message_set_flag (message, NOTMUCH_MESSAGE_FLAG_EXCLUDED, true);
 
     return message;
 }
@@ -430,7 +430,7 @@ _notmuch_mset_messages_move_to_next (notmuch_messages_t *messages)
     mset_messages->iterator++;
 }
 
-static notmuch_bool_t
+static bool
 _notmuch_doc_id_set_init (void *ctx,
 			  notmuch_doc_id_set_t *doc_ids,
 			  GArray *arr)
@@ -443,7 +443,7 @@ _notmuch_doc_id_set_init (void *ctx,
     bitmap = talloc_zero_array (ctx, unsigned char, DOCIDSET_WORD(max) + 1);
 
     if (bitmap == NULL)
-	return FALSE;
+	return false;
 
     doc_ids->bitmap = bitmap;
     doc_ids->bound = max + 1;
@@ -453,15 +453,15 @@ _notmuch_doc_id_set_init (void *ctx,
 	bitmap[DOCIDSET_WORD(doc_id)] |= 1 << DOCIDSET_BIT(doc_id);
     }
 
-    return TRUE;
+    return true;
 }
 
-notmuch_bool_t
+bool
 _notmuch_doc_id_set_contains (notmuch_doc_id_set_t *doc_ids,
 			      unsigned int doc_id)
 {
     if (doc_id >= doc_ids->bound)
-	return FALSE;
+	return false;
     return doc_ids->bitmap[DOCIDSET_WORD(doc_id)] & (1 << DOCIDSET_BIT(doc_id));
 }
 
@@ -514,7 +514,7 @@ notmuch_query_search_threads (notmuch_query_t *query,
 	return status;
     }
 
-    threads->doc_ids = g_array_new (FALSE, FALSE, sizeof (unsigned int));
+    threads->doc_ids = g_array_new (false, false, sizeof (unsigned int));
     while (notmuch_messages_valid (messages)) {
 	unsigned int doc_id = _notmuch_mset_messages_get_doc_id (messages);
 	g_array_append_val (threads->doc_ids, doc_id);
@@ -546,7 +546,7 @@ notmuch_threads_valid (notmuch_threads_t *threads)
     unsigned int doc_id;
 
     if (! threads)
-	return FALSE;
+	return false;
 
     while (threads->doc_id_pos < threads->doc_ids->len) {
 	doc_id = g_array_index (threads->doc_ids, unsigned int,
diff --git a/lib/string-map.c b/lib/string-map.c
index 0bb77e93..5aac8bcc 100644
--- a/lib/string-map.c
+++ b/lib/string-map.c
@@ -33,14 +33,14 @@ typedef struct _notmuch_string_pair_t {
 } notmuch_string_pair_t;
 
 struct _notmuch_string_map {
-    notmuch_bool_t sorted;
+    bool sorted;
     size_t length;
     notmuch_string_pair_t *pairs;
 };
 
 struct _notmuch_string_map_iterator {
     notmuch_string_pair_t *current;
-    notmuch_bool_t exact;
+    bool exact;
     const char *key;
 };
 
@@ -55,7 +55,7 @@ _notmuch_string_map_create (const void *ctx)
 
     map->length = 0;
     map->pairs = NULL;
-    map->sorted = TRUE;
+    map->sorted = true;
 
     return map;
 }
@@ -67,7 +67,7 @@ _notmuch_string_map_append (notmuch_string_map_t *map,
 {
 
     map->length++;
-    map->sorted = FALSE;
+    map->sorted = false;
 
     if (map->pairs)
 	map->pairs = talloc_realloc (map, map->pairs, notmuch_string_pair_t, map->length + 1);
@@ -103,11 +103,11 @@ _notmuch_string_map_sort (notmuch_string_map_t *map)
 
     qsort (map->pairs, map->length, sizeof (notmuch_string_pair_t), cmppair);
 
-    map->sorted = TRUE;
+    map->sorted = true;
 }
 
-static notmuch_bool_t
-string_cmp (const char *a, const char *b, notmuch_bool_t exact)
+static bool
+string_cmp (const char *a, const char *b, bool exact)
 {
     if (exact)
 	return (strcmp (a, b));
@@ -116,7 +116,7 @@ string_cmp (const char *a, const char *b, notmuch_bool_t exact)
 }
 
 static notmuch_string_pair_t *
-bsearch_first (notmuch_string_pair_t *array, size_t len, const char *key, notmuch_bool_t exact)
+bsearch_first (notmuch_string_pair_t *array, size_t len, const char *key, bool exact)
 {
     size_t first = 0;
     size_t last = len - 1;
@@ -151,7 +151,7 @@ _notmuch_string_map_get (notmuch_string_map_t *map, const char *key)
     /* this means that calling append invalidates iterators */
     _notmuch_string_map_sort (map);
 
-    pair = bsearch_first (map->pairs, map->length, key, TRUE);
+    pair = bsearch_first (map->pairs, map->length, key, true);
     if (! pair)
 	return NULL;
 
@@ -160,7 +160,7 @@ _notmuch_string_map_get (notmuch_string_map_t *map, const char *key)
 
 notmuch_string_map_iterator_t *
 _notmuch_string_map_iterator_create (notmuch_string_map_t *map, const char *key,
-				     notmuch_bool_t exact)
+				     bool exact)
 {
     notmuch_string_map_iterator_t *iter;
 
@@ -179,15 +179,15 @@ _notmuch_string_map_iterator_create (notmuch_string_map_t *map, const char *key,
     return iter;
 }
 
-notmuch_bool_t
+bool
 _notmuch_string_map_iterator_valid (notmuch_string_map_iterator_t *iterator)
 {
     if (iterator->current == NULL)
-	return FALSE;
+	return false;
 
     /* sentinel */
     if (iterator->current->key == NULL)
-	return FALSE;
+	return false;
 
     return (0 == string_cmp (iterator->key, iterator->current->key, iterator->exact));
 
diff --git a/lib/thread.cc b/lib/thread.cc
index e17ef63e..1632da4c 100644
--- a/lib/thread.cc
+++ b/lib/thread.cc
@@ -59,12 +59,12 @@ _notmuch_thread_destructor (notmuch_thread_t *thread)
     g_hash_table_unref (thread->message_hash);
 
     if (thread->authors_array) {
-	g_ptr_array_free (thread->authors_array, TRUE);
+	g_ptr_array_free (thread->authors_array, true);
 	thread->authors_array = NULL;
     }
 
     if (thread->matched_authors_array) {
-	g_ptr_array_free (thread->matched_authors_array, TRUE);
+	g_ptr_array_free (thread->matched_authors_array, true);
 	thread->matched_authors_array = NULL;
     }
 
@@ -156,9 +156,9 @@ _resolve_thread_authors_string (notmuch_thread_t *thread)
 	first_non_matched_author = 0;
     }
 
-    g_ptr_array_free (thread->authors_array, TRUE);
+    g_ptr_array_free (thread->authors_array, true);
     thread->authors_array = NULL;
-    g_ptr_array_free (thread->matched_authors_array, TRUE);
+    g_ptr_array_free (thread->matched_authors_array, true);
     thread->matched_authors_array = NULL;
 }
 
@@ -239,7 +239,7 @@ _thread_add_message (notmuch_thread_t *thread,
     InternetAddress *address;
     const char *from, *author;
     char *clean_author;
-    notmuch_bool_t message_excluded = FALSE;
+    bool message_excluded = false;
 
     if (omit_exclude != NOTMUCH_EXCLUDE_FALSE) {
 	for (tags = notmuch_message_get_tags (message);
@@ -254,7 +254,7 @@ _thread_add_message (notmuch_thread_t *thread,
 	    {
 		/* Check for an empty string, and then ignore initial 'K'. */
 		if (*(term->string) && strcmp(tag, (term->string + 1)) == 0) {
-		    message_excluded = TRUE;
+		    message_excluded = true;
 		    break;
 		}
 	    }
@@ -310,7 +310,7 @@ _thread_add_message (notmuch_thread_t *thread,
 
     /* Mark excluded messages. */
     if (message_excluded)
-	notmuch_message_set_flag (message, NOTMUCH_MESSAGE_FLAG_EXCLUDED, TRUE);
+	notmuch_message_set_flag (message, NOTMUCH_MESSAGE_FLAG_EXCLUDED, true);
 }
 
 static void