diff --git a/main.c b/main.c
index 2b2e0a4..2902a03 100644
--- a/main.c
+++ b/main.c
@@ -128,7 +128,7 @@ int main(int argc, char **argv) {
 
     while (1) {
         int option_index;
-        char c;
+        int c;
         static struct option long_options[] = 
         {
             {"extract", 0, NULL, 'x'},