diff --git a/lib/preprocessor.cpp b/lib/preprocessor.cpp
index 6e5e743cc..61ad4a6eb 100644
--- a/lib/preprocessor.cpp
+++ b/lib/preprocessor.cpp
@@ -1001,13 +1001,17 @@ std::list<std::string> Preprocessor::getcfgs(const std::string &filedata, const
         }
 
         if (line.compare(0, 8, "#define ") == 0) {
-            bool valid = true;
+            bool valid = false;
             for (std::string::size_type pos = 8; pos < line.size(); ++pos) {
                 char ch = line[pos];
-                if (ch=='_' || (ch>='a' && ch<='z') || (ch>='A' && ch<='Z') || (pos>8 && ch>='0' && ch<='9'))
+                if (ch=='_' || (ch>='a' && ch<='z') || (ch>='A' && ch<='Z') || (pos>8 && ch>='0' && ch<='9')) {
+                    valid = true;
                     continue;
-                if (ch==' ' || ch=='(')
-                    break;
+                }
+                if (ch==' ' || ch=='(') {
+                    if (valid)
+                        break;
+                }
                 valid = false;
                 break;
             }
diff --git a/test/testpreprocessor.cpp b/test/testpreprocessor.cpp
index d059e81ec..ea83acf92 100644
--- a/test/testpreprocessor.cpp
+++ b/test/testpreprocessor.cpp
@@ -232,7 +232,8 @@ private:
         TEST_CASE(testPreprocessorRead3);
         TEST_CASE(testPreprocessorRead4);
 
-        TEST_CASE(invalid_define);	// #2605 - hang for: '#define ='
+        TEST_CASE(invalid_define_1);	// #2605 - hang for: '#define ='
+        TEST_CASE(invalid_define_2);	// #4036 - hang for: '#define () {(int f(x) }'
 
         // Show 'missing include' warnings
         TEST_CASE(missingInclude);
@@ -2955,7 +2956,7 @@ private:
         }
     }
 
-    void invalid_define() {
+    void invalid_define_1() {
         Settings settings;
         Preprocessor preprocessor(&settings, this);
 
@@ -2966,6 +2967,17 @@ private:
         preprocessor.preprocess(src, processedFile, cfg, "", paths); // don't hang
     }
 
+    void invalid_define_2() {  // #4036 - hang
+        Settings settings;
+        Preprocessor preprocessor(&settings, this);
+
+        std::istringstream src("#define () {(int f(x) }\n");
+        std::string processedFile;
+        std::list<std::string> cfg;
+        std::list<std::string> paths;
+        preprocessor.preprocess(src, processedFile, cfg, "", paths); // don't hang
+    }
+
     void missingInclude() {
         Settings settings;
         Preprocessor preprocessor(&settings, this);