From 073c12600b554650c8d838609d1dd71dde8a9cef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20Quei=C3=9Fner?= <git@mq32.de>
Date: Fri, 1 Jul 2016 19:29:43 +0200
Subject: [PATCH] Adds usability features.

---
 libvm/as/as.c   |  7 ++++++-
 libvm/explink.c | 22 +++++++++++++++-------
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/libvm/as/as.c b/libvm/as/as.c
index e8726f0..e404b66 100644
--- a/libvm/as/as.c
+++ b/libvm/as/as.c
@@ -286,12 +286,17 @@ int main(int argc, char **argv)
 		}
 	}
 	
+  if(optind >= argc) {
+    fprintf(stderr, "No input files.\n");
+    exit(1);
+  }
+	
 	if(output == NULL)
 	{
 		fprintf(stderr, "An output file must be given by -o fileName\n");
 		exit(1);
 	}
-	
+  
 	for (int index = optind; index < argc; index++)
 	{
 		FILE *f = fopen(argv[index], "r");
diff --git a/libvm/explink.c b/libvm/explink.c
index 186c7a9..36dc97d 100644
--- a/libvm/explink.c
+++ b/libvm/explink.c
@@ -72,19 +72,27 @@ int main(int argc, char **argv)
 	for (int index = optind; index < argc; index++)
 		printf("Non-option argument %s\n", argv[index]);
 
+	///////////////////////////////////////////////////////////////////////////////
+
+	// fprintf(stderr, "Out:  %s\n", outfileName);
+	// fprintf(stderr, "Code: %s\n", codefileName);
+	// fprintf(stderr, "Data: %s\n", datafileName);
+
+  if(!codefileName && !datafileName)
+  {
+    fprintf(stderr, "No input files.\n");
+    exit(1);
+  }
+  
+  ///////////////////////////////////////////////////////////////////////////////
+    
 	FILE *f = fopen(outfileName, "wb");
 	if (f == NULL)
 	{
 		fprintf(stderr, "Could not open file %s\n", outfileName);
 		return 1;
 	}
-
-	///////////////////////////////////////////////////////////////////////////////
-
-	fprintf(stderr, "Out:  %s\n", outfileName);
-	fprintf(stderr, "Code: %s\n", codefileName);
-	fprintf(stderr, "Data: %s\n", datafileName);
-
+  
 	///////////////////////////////////////////////////////////////////////////////
 
 	int numSections = 0;