Fix return code if arguments can not be parsed

pom.xml

@@ -30,7 +30,7 @@
 
     <groupId>de.monticore.lang.monticar</groupId>
     <artifactId>embedded-montiarc-math-generator</artifactId>
-    <version>0.1.10</version>
+    <version>0.1.11-SNAPSHOT</version>
 
     <!-- == PROJECT DEPENDENCIES ============================================= -->
 

src/main/java/de/monticore/lang/monticar/generator/cpp/GeneratorCppCli.java

@@ -145,6 +145,9 @@ public final class GeneratorCppCli {
         CommandLine cliArgs = parseArgs(options, parser, args);
         if (cliArgs != null) {
             runGenerator(cliArgs);
+        }else{
+            Log.error("Error parsing cli arguments!");
+            System.exit(1);
         }
     }