diff --git a/src/main.cpp b/src/main.cpp
index 78e0f10..a3b5c36 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -42,7 +42,7 @@ int main(int argc, char* argv[]) {
     if (!files.empty()) {
         vector<future<pair<string, optional<Yerbacon::Exception>>>> Units(files.size());
         const launch& Policy = not parallel ? launch::deferred : launch::async;
-        transform(files.begin(), files.end(), Units.begin(), [&Policy, &compile](const string_view& fileName){
+        transform(files.cbegin(), files.cend(), Units.begin(), [&Policy, &compile](const string_view& fileName){
             return async(Policy, [&fileName, &compile]() {
                 pair<string, optional<Yerbacon::Exception>> resultingPair;
                 try {