diff --git a/ccid/src/binutil.c b/ccid/src/binutil.c
index bc7c37d..87879f7 100644
--- a/ccid/src/binutil.c
+++ b/ccid/src/binutil.c
@@ -54,7 +54,7 @@ void print_usage(const char *app_name, const struct option options[],
                 break;
         }
         snprintf(buf, sizeof buf, "--%-13s%s%s", options[i].name, tmp, arg_str);
-        if (strnlen(buf, sizeof buf) > 24) {
+        if (strlen(buf) > 24) {
             printf("  %s\n", buf);
             buf[0] = '\0';
         }