diff --git a/main.cpp b/main.cpp
index 9e9c4b1d..ecbe062f 100644
--- a/main.cpp
+++ b/main.cpp
@@ -166,6 +166,9 @@ int main(int argc, char **argv)
             case simplecpp::Output::EXPLICIT_INCLUDE_NOT_FOUND:
                 std::cerr << "explicit include not found: ";
                 break;
+            case simplecpp::Output::FILE_NOT_FOUND:
+                std::cerr << "file not found: ";
+                break;
             }
             std::cerr << output.msg << std::endl;
         }
diff --git a/simplecpp.cpp b/simplecpp.cpp
index e8636aaa..d9fd0087 100755
--- a/simplecpp.cpp
+++ b/simplecpp.cpp
@@ -385,7 +385,10 @@ class FileStream : public simplecpp::TokenList::Stream {
         , lastCh(0)
         , lastStatus(0)
     {
-        assert(file != nullptr);
+        if (!file) {
+            const std::vector<std::string> location;
+            throw simplecpp::Output(location, simplecpp::Output::FILE_NOT_FOUND, "File is missing: " + filename);
+        }
         init();
     }
 
@@ -442,8 +445,15 @@ simplecpp::TokenList::TokenList(std::istream &istr, std::vector<std::string> &fi
 simplecpp::TokenList::TokenList(const std::string &filename, std::vector<std::string> &filenames, OutputList *outputList)
         : frontToken(nullptr), backToken(nullptr), files(filenames)
 {
-    FileStream stream(filename);
-    readfile(stream,filename,outputList);
+    try
+    {
+        FileStream stream(filename);
+        readfile(stream,filename,outputList);
+    }
+    catch(const simplecpp::Output & e) // TODO handle extra type of errors
+    {
+        outputList->push_back(e);
+    }
 }
 
 simplecpp::TokenList::TokenList(const TokenList &other) : frontToken(nullptr), backToken(nullptr), files(other.files)
diff --git a/simplecpp.h b/simplecpp.h
index e5745a1a..5ad44a09 100755
--- a/simplecpp.h
+++ b/simplecpp.h
@@ -180,8 +180,10 @@ namespace simplecpp {
             SYNTAX_ERROR,
             PORTABILITY_BACKSLASH,
             UNHANDLED_CHAR_ERROR,
-            EXPLICIT_INCLUDE_NOT_FOUND
+            EXPLICIT_INCLUDE_NOT_FOUND,
+            FILE_NOT_FOUND
         } type;
+        explicit Output(const std::vector<std::string> &files, Output::Type id, const std::string & errMsg ) : type(id), location(files), msg(errMsg) {}
         Location location;
         std::string msg;
     };
diff --git a/test.cpp b/test.cpp
index 2bbf861d..9588441c 100644
--- a/test.cpp
+++ b/test.cpp
@@ -150,6 +150,10 @@ static std::string toString(const simplecpp::OutputList &outputList)
             break;
         case simplecpp::Output::Type::EXPLICIT_INCLUDE_NOT_FOUND:
             ostr << "explicit_include_not_found,";
+            break;
+        case simplecpp::Output::Type::FILE_NOT_FOUND:
+            ostr << "file_not_found,";
+            break;
         }
 
         ostr << output.msg << '\n';
@@ -2266,6 +2270,14 @@ static void readfile_error()
                   "X",readfile("#if !A\n#error\n#endif\nX\n"));
 }
 
+static void readfile_file_not_found()
+{
+    simplecpp::OutputList outputList;
+    std::vector<std::string> files;
+    (void)simplecpp::TokenList("NotAFile", files, &outputList);
+    ASSERT_EQUALS("file0,1,file_not_found,File is missing: NotAFile\n", toString(outputList));
+}
+
 static void stringify1()
 {
     const char code_c[] = "#include \"A.h\"\n"
@@ -2891,6 +2903,7 @@ int main(int argc, char **argv)
     TEST_CASE(readfile_cpp14_number);
     TEST_CASE(readfile_unhandled_chars);
     TEST_CASE(readfile_error);
+    TEST_CASE(readfile_file_not_found);
 
     TEST_CASE(stringify1);