1 files changed, 1 insertions, 1 deletions
diff --git a/io.c b/io.c
index 2bf7cd7512..5c8a66d143 100644
--- a/io.c
+++ b/io.c
@@ -2506,7 +2506,7 @@ io_getpartial(int argc, VALUE *argv, VALUE io, VALUE opts, int nonblock)
     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);