diff --git a/libisoburn/trunk/test/compare_file.c b/libisoburn/trunk/test/compare_file.c
index 47be2f41..d554c4e8 100644
--- a/libisoburn/trunk/test/compare_file.c
+++ b/libisoburn/trunk/test/compare_file.c
@@ -13,6 +13,10 @@
   cc -g -o compare_file compare_file.c
 */
 
+#ifdef HAVE_CONFIG_H
+#include "../config.h"
+#endif
+
 #include <ctype.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ -250,6 +254,12 @@ int main(int argc, char **argv)
  int ret, i, with_ctime= 1;
  char adr1[4096], adr2[4096], adrc[4096];
 
+ if(sizeof(off_t) < 8) {
+   fprintf(stderr,
+    "%s : FATAL : Compile time misconfiguration. sizeof(off_t) too small.\n\n",
+    argv[0]);
+   exit(4);
+ }
  if(argc<4) {
    fprintf(stderr, "usage: %s  path  prefix1  prefix2\n", argv[0]);
    exit(2);
@@ -259,7 +269,7 @@ int main(int argc, char **argv)
      with_ctime= 0;
    else {
      fprintf(stderr, "%s : Option not recognized: '%s'\n", argv[0], argv[i]);
-     exit(1);
+     exit(2);
    }
  }