diff --git a/client/maxadmin.c b/client/maxadmin.c
index d7e4856cd..305ae3700 100644
--- a/client/maxadmin.c
+++ b/client/maxadmin.c
@@ -142,7 +142,7 @@ main(int argc, char **argv)
     bool use_unix_socket = false;
 
     int option_index = 0;
-    char c;
+    int c;
     while ((c = getopt_long(argc, argv, "h:p::P:u:S:v?ei",
                             long_options, &option_index)) >= 0)
     {
diff --git a/server/modules/routing/binlogrouter/maxbinlogcheck.c b/server/modules/routing/binlogrouter/maxbinlogcheck.c
index 820b9aa3d..1585a4789 100644
--- a/server/modules/routing/binlogrouter/maxbinlogcheck.c
+++ b/server/modules/routing/binlogrouter/maxbinlogcheck.c
@@ -86,7 +86,7 @@ int main(int argc, char **argv)
     char *key_file = NULL;
     char *aes_algo = NULL;
     int report_header = 0;
-    char c;
+    int c;
 
     while ((c = getopt_long(argc, argv, "dVfMHK:A:?", long_options, &option_index)) >= 0)
     {