From 3ecff9bcc65b707e5fa2c4bfb29aa7a934f0ce30 Mon Sep 17 00:00:00 2001
From: Wolfgang Thaller <wolfgang.thaller@gmx.net>
Date: Sun, 15 Oct 2017 12:48:44 +0200
Subject: [PATCH] ConvertObj: check command line args (fixes #34)

---
 ConvertObj/ConvertObj.cc | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/ConvertObj/ConvertObj.cc b/ConvertObj/ConvertObj.cc
index 7c15248129..7fb59121cd 100644
--- a/ConvertObj/ConvertObj.cc
+++ b/ConvertObj/ConvertObj.cc
@@ -219,7 +219,18 @@ void sortModules(std::vector<std::shared_ptr<Module>>& modules)
 
 int main(int argc, char* argv[])
 {
+	if(argc != 2)
+	{
+		std::cerr << "Usage: ConvertOBJ mpw.o > retro68.s\n";
+		return 1;
+	}
 	std::ifstream in(argv[1]);
+	if(!in)
+	{
+		std::cerr << "Could not read imput file \"" << argv[1] << "\"\n";
+		std::cerr << "Usage: ConvertOBJ mpw.o > retro68.s\n";
+		return 1;
+	}
 
 	unordered_map<int,string>	stringDictionary;