1 files changed, 1 insertions, 1 deletions
diff --git a/io.c b/io.c
index 086fc358e3..8c60128e0f 100644
--- a/io.c
+++ b/io.c
@@ -2419,7 +2419,7 @@ io_getpartial(int argc, VALUE *argv, VALUE io, int nonblock, int no_exception)
     long n, len;
     struct read_internal_arg arg;
 
-    rb_scan_args(argc, argv, "11:", &length, &str, NULL);
+    rb_scan_args(argc, argv, "11", &length, &str);
 
     if ((len = NUM2LONG(length)) < 0) {
 	rb_raise(rb_eArgError, "negative length %ld given", len);