From 37dc1f9b071e2452ea0e6ee90f570f17d1e0b218 Mon Sep 17 00:00:00 2001
From: Stefan Haustein <stefan.haustein@gmail.com>
Date: Sun, 5 Jul 2020 13:15:42 +0200
Subject: [PATCH] Add an explicit error message for files that can't be opened

---
 src/main/cpp/tiv.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/main/cpp/tiv.cpp b/src/main/cpp/tiv.cpp
index bafdd0d..2c9074a 100644
--- a/src/main/cpp/tiv.cpp
+++ b/src/main/cpp/tiv.cpp
@@ -1,6 +1,7 @@
 #include <iostream>
 #include <bitset>
 #include <cmath>
+#include <fstream> 
 #include <map>
 #include <string>
 #include <vector>
@@ -506,7 +507,12 @@ int main(int argc, char* argv[]) {
            }
          }
       } else {
-        file_names.push_back(arg);
+        std::ifstream fin(arg.c_str());
+        if (fin) {
+          file_names.push_back(arg);
+        } else {
+          std::cerr << "Can't open file (permission?): " << arg << std::endl;
+        }
       }
     }
   }