diff --git a/src/util/filemanager.c b/src/util/filemanager.c
index 7a4469f..1d4e643 100644
--- a/src/util/filemanager.c
+++ b/src/util/filemanager.c
@@ -58,12 +58,12 @@ void delete_file_manager(file_handle_t *file_handle) {
 }
 
 
-void get_filename(file_handle_t *file_handle, char **filename, size_t *size)
+int get_filename(file_handle_t *file_handle, char **filename)
 //
 // BE AWARE: The memory allocated here must be freed by the caller
 //
 {
-    copy_cstr(file_handle->filename, filename);
+    return copy_cstr(file_handle->filename, filename);
 }
 
 
@@ -171,7 +171,7 @@ int _fopen(FILE **f, const char *name, const char *mode)
 {
     int ret = 0;
 
-#ifdef _WIN32
+#ifdef _MSC_VER
     ret = (int)fopen_s(f, name, mode);
 #else
     *f = fopen(name, mode);
diff --git a/src/util/filemanager.h b/src/util/filemanager.h
index 93ee8d9..68bd7c2 100644
--- a/src/util/filemanager.h
+++ b/src/util/filemanager.h
@@ -44,7 +44,7 @@ file_handle_t *create_file_manager();
 void delete_file_manager(file_handle_t *file_handle);
 
 
-void get_filename(file_handle_t *file_handle, char **filename, size_t *size);
+int get_filename(file_handle_t *file_handle, char **filename);
 
 
 int open_file(file_handle_t *file_handle, const char *filename, const char *file_mode);
diff --git a/tests/test_link.cpp b/tests/test_link.cpp
index 15f451e..aa20d23 100644
--- a/tests/test_link.cpp
+++ b/tests/test_link.cpp
@@ -11,6 +11,8 @@
  ******************************************************************************
 */
 
+#include <math.h>
+
 #include <boost/test/unit_test.hpp>
 
 #include "test_toolkit.hpp"
diff --git a/tests/util/test_errormanager.cpp b/tests/util/test_errormanager.cpp
index f9a88b6..43f59e2 100644
--- a/tests/util/test_errormanager.cpp
+++ b/tests/util/test_errormanager.cpp
@@ -15,10 +15,10 @@ void mock_lookup(int errcode, char *errmsg, int len)
     char *msg = NULL;
 
     if (errcode == 100) {
-        msg = MESSAGE_STRING;
+        msg = (char *)MESSAGE_STRING;
     }
     else {
-        msg = "";
+        msg = (char *)"";
     }
     strncpy(errmsg, msg, len);
 }
diff --git a/tests/util/test_filemanager.cpp b/tests/util/test_filemanager.cpp
index 70ff6c6..7e17577 100644
--- a/tests/util/test_filemanager.cpp
+++ b/tests/util/test_filemanager.cpp
@@ -82,12 +82,12 @@ struct Fixture{
 BOOST_FIXTURE_TEST_CASE(test_temp_file, Fixture)
 {
     char *filename;
-    size_t size;
 
     printf_file(file_handle, "%s", "This is a test.");
 
-    get_filename(file_handle, &filename, &size);
-	BOOST_CHECK(is_valid(file_handle) == true);
+    error = get_filename(file_handle, &filename);
+    BOOST_REQUIRE(error == 0);
+    BOOST_CHECK(is_valid(file_handle) == true);
 
     BOOST_CHECK(boost::filesystem::exists(filename) == true);