diff --git a/src/of_str.cpp b/src/of_str.cpp
index 470abe4..b35632f 100644
--- a/src/of_str.cpp
+++ b/src/of_str.cpp
@@ -33,11 +33,11 @@ std::vector<ofString> COfStr::split(const ofString& input, const ofString& delim
 }
 ofString COfStr::trim(const ofString& input)
 {
-    size_t start = input.find_first_not_of(" \t\n\r\f\v");
+    size_t start = input.find_first_not_of(ofT(" \t\n\r\f\v"));
     if (start == std::string::npos) {
-        return "";
+        return ofT("");
     }
-    size_t end = input.find_last_not_of(" \t\n\r\f\v");
+    size_t end = input.find_last_not_of(ofT(" \t\n\r\f\v"));
     return input.substr(start, end - start + 1);
 }
 }   // namespace ofen
diff --git a/src/of_util.cpp b/src/of_util.cpp
index e355241..9a7eeaf 100644
--- a/src/of_util.cpp
+++ b/src/of_util.cpp
@@ -74,9 +74,15 @@ ofString OfUtil::now_time()
 #else
     localtime_r(&time_t_now, &tm_now);
 #endif
-    std::ostringstream oss;
-    oss << std::put_time(&tm_now, "%Y-%m-%d %H:%M:%S");
+#ifdef UNICODE_OFSTR
+    std::wostringstream oss;
+    oss << std::put_time(&tm_now, ofT("%Y-%m-%d %H:%M:%S"));
     return oss.str();
+#else
+    std::ostringstream oss;
+    oss << std::put_time(&tm_now, ofT("%Y-%m-%d %H:%M:%S"));
+    return oss.str();
+#endif
 }
 
 #ifdef _WIN32