diff --git a/simplecpp.cpp b/simplecpp.cpp
index bc6ca41..d2fa6ee 100755
--- a/simplecpp.cpp
+++ b/simplecpp.cpp
@@ -3360,12 +3360,14 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
     macros.insert(std::make_pair("__TIME__", Macro("__TIME__", getTimeDefine(&ltime), dummy)));
 
     if (!dui.std.empty()) {
-        std::string std_def = simplecpp::getCStdString(dui.std);
-        if (!std_def.empty()) {
-            macros.insert(std::make_pair("__STDC_VERSION__", Macro("__STDC_VERSION__", std_def, dummy)));
+        const cstd_t c_std = simplecpp::getCStd(dui.std);
+        if (c_std != CUnknown) {
+            const std::string std_def = simplecpp::getCStdString(c_std);
+            if (!std_def.empty())
+                macros.insert(std::make_pair("__STDC_VERSION__", Macro("__STDC_VERSION__", std_def, dummy)));
         } else {
-            std_def = simplecpp::getCppStdString(dui.std);
-            if (std_def.empty()) {
+            const cppstd_t cpp_std = simplecpp::getCppStd(dui.std);
+            if (cpp_std == CPPUnknown) {
                 if (outputList) {
                     simplecpp::Output err(files);
                     err.type = Output::DUI_ERROR;
@@ -3375,7 +3377,9 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
                 output.clear();
                 return;
             }
-            macros.insert(std::make_pair("__cplusplus", Macro("__cplusplus", std_def, dummy)));
+            const std::string std_def = simplecpp::getCppStdString(cpp_std);
+            if (!std_def.empty())
+                macros.insert(std::make_pair("__cplusplus", Macro("__cplusplus", std_def, dummy)));
         }
     }
 
diff --git a/test.cpp b/test.cpp
index 6b7cdc9..3a4999a 100644
--- a/test.cpp
+++ b/test.cpp
@@ -2718,6 +2718,33 @@ static void stdEnum()
     ASSERT_EQUALS(simplecpp::cppstd_t::CPPUnknown, simplecpp::getCppStd("c11"));
 }
 
+static void stdValid()
+{
+    const char code[] = "";
+    simplecpp::DUI dui;
+    simplecpp::OutputList outputList;
+
+    dui.std = "c89";
+    ASSERT_EQUALS("", preprocess(code, dui, &outputList));
+    ASSERT_EQUALS(0, outputList.size());
+    outputList.clear();
+
+    dui.std = "gnu23";
+    ASSERT_EQUALS("", preprocess(code, dui, &outputList));
+    ASSERT_EQUALS(0, outputList.size());
+    outputList.clear();
+
+    dui.std = "c++03";
+    ASSERT_EQUALS("", preprocess(code, dui, &outputList));
+    ASSERT_EQUALS(0, outputList.size());
+    outputList.clear();
+
+    dui.std = "gnu++26";
+    ASSERT_EQUALS("", preprocess(code, dui, &outputList));
+    ASSERT_EQUALS(0, outputList.size());
+    outputList.clear();
+}
+
 static void assertToken(const std::string& s, bool name, bool number, bool comment, char op, int line)
 {
     const std::vector<std::string> f;
@@ -3048,6 +3075,7 @@ int main(int argc, char **argv)
     TEST_CASE(cpluscplusDefine);
     TEST_CASE(invalidStd);
     TEST_CASE(stdEnum);
+    TEST_CASE(stdValid);
 
     TEST_CASE(token);