diff --git a/lib/cppcheck.cpp b/lib/cppcheck.cpp
index a7e2ae39b..adde9792f 100644
--- a/lib/cppcheck.cpp
+++ b/lib/cppcheck.cpp
@@ -40,7 +40,7 @@
 	- rename "file" to "single"
 	- synchronise map access in multithreaded mode or disable timing
 	- add unit tests
-		- for --showtime
+		- for --showtime (needs input file)
 		- for Timer* classes
 	- move timer stuff to seperate source/header
 */
@@ -669,7 +669,11 @@ unsigned int CppCheck::check()
                 if (_settings._errorsOnly == false && it != configurations.begin())
                     _errorLogger.reportOut(std::string("Checking ") + fname + ": " + cfg + std::string("..."));
 
-                checkFile(codeWithoutCfg + _settings.append(), _filenames[c].c_str());
+                std::string appendCode = _settings.append();
+                if( !appendCode.empty() )
+                    Preprocessor::preprocessWhitespaces(appendCode);
+
+                checkFile(codeWithoutCfg + appendCode, _filenames[c].c_str());
                 ++checkCount;
             }
         }
diff --git a/lib/preprocessor.cpp b/lib/preprocessor.cpp
index 8c0ceb32a..304ebca57 100644
--- a/lib/preprocessor.cpp
+++ b/lib/preprocessor.cpp
@@ -568,10 +568,8 @@ std::string Preprocessor::replaceIfDefined(const std::string &str)
     return ret;
 }
 
-void Preprocessor::preprocess(std::istream &srcCodeStream, std::string &processedFile, std::list<std::string> &resultConfigurations, const std::string &filename, const std::list<std::string> &includePaths)
+void Preprocessor::preprocessWhitespaces(std::string &processedFile)
 {
-    processedFile = read(srcCodeStream, filename, _settings);
-
     // Replace all tabs with spaces..
     std::replace(processedFile.begin(), processedFile.end(), '\t', ' ');
 
@@ -581,6 +579,14 @@ void Preprocessor::preprocess(std::istream &srcCodeStream, std::string &processe
 
     // Remove space characters that are after or before new line character
     processedFile = removeSpaceNearNL(processedFile);
+}
+
+void Preprocessor::preprocess(std::istream &srcCodeStream, std::string &processedFile, std::list<std::string> &resultConfigurations, const std::string &filename, const std::list<std::string> &includePaths)
+{
+    processedFile = read(srcCodeStream, filename, _settings);
+
+    // normalize the whitespaces of the file
+    preprocessWhitespaces(processedFile);
 
     // Remove asm(...)
     removeAsm(processedFile);
diff --git a/lib/preprocessor.h b/lib/preprocessor.h
index d3e1e3fad..e180c7a22 100644
--- a/lib/preprocessor.h
+++ b/lib/preprocessor.h
@@ -91,6 +91,12 @@ public:
      */
     static void simplifyCondition(const std::map<std::string, std::string> &variables, std::string &condition, bool match);
 
+    /**
+     * preprocess all whitespaces
+     * @param processedFile The data to be processed
+     */
+    static void preprocessWhitespaces(std::string &processedFile);
+
 protected:
 
     /**