Issue 224: add -fno-lto flag

setup.py

@@ -153,7 +153,15 @@ def add_filters(filters, pkgs, pkgs_data):
 if sys.platform == "win32":
     pass
 else:
-    arguments = ['-std=c++17', '-Wall', '-Wextra', '-fdiagnostics-show-option']
+    # old version
+    # arguments = ['-std=c++17', '-Wall', '-Wextra',
+    #              '-fdiagnostics-show-option']
+    # lto does not work
+    # arguments = ['-std=c++17', '-Wall', '-Wextra',
+    #       '-fdiagnostics-show-option', '-flto=auto', '-ffat-lto-objects']
+    # no-lto to be on the save side
+    arguments = ['-std=c++17', '-Wall', '-Wextra', '-fdiagnostics-show-option',
+                 '-fno-lto']
     nexus_config.add_compiler_arguments(arguments)
 
 # ----------------------------------------------------------------------------

test/h5cpp_tests/node_tests/dataset_io_test.py

@@ -131,6 +131,21 @@ def testWriteVariableLengthUTF8Scalar(self):
         else:
             self.assertEqual(read, bdata)
 
+    def testWriteVariableLengthEmptyScalar(self):
+        data = u""
+        bdata = b""
+        dtype = h5cpp.datatype.String.variable()
+        # dtype.encoding = h5cpp.datatype.CharacterEncoding.UTF8
+        dataset = Dataset(
+            self.root, h5cpp.Path("VariableLengthStringEmptyScalar"),
+            dtype, Scalar())
+        # dataset.write(data)
+        read = dataset.read()
+        if sys.version_info > (3,):
+            self.assertEqual(read, data)
+        else:
+            self.assertEqual(read, bdata)
+
     def testWriteIntegerArray(self):
 
         data = numpy.array([[1, 2, 3, 4], [5, 6, 7, 8]])