1 files changed, 1 insertions, 1 deletions
diff --git a/io.c b/io.c
index 3153ff7c23..16cb9b5607 100644
--- a/io.c
+++ b/io.c
@@ -8408,7 +8408,7 @@ rb_io_set_encoding(int argc, VALUE *argv, VALUE io)
 }
 
 void
-rb_stdio_set_default_encoding()
+rb_stdio_set_default_encoding(void)
 {
     extern VALUE rb_stdin, rb_stdout, rb_stderr;
     VALUE val = Qnil;