--- IO-AIO/AIO.pm	2005/07/11 01:49:14	1.13
+++ IO-AIO/AIO.pm	2005/07/11 02:53:59	1.14
@@ -77,11 +77,11 @@
 
 All the C<aio_*> calls are more or less thin wrappers around the syscall
 with the same name (sans C<aio_>). The arguments are similar or identical,
-and they all accept an additional C<$callback> argument which must be
-a code reference. This code reference will get called with the syscall
-return code (e.g. most syscalls return C<-1> on error, unlike perl, which
-usually delivers "false") as it's sole argument when the given syscall has
-been executed asynchronously.
+and they all accept an additional (and optional) C<$callback> argument
+which must be a code reference. This code reference will get called with
+the syscall return code (e.g. most syscalls return C<-1> on error, unlike
+perl, which usually delivers "false") as it's sole argument when the given
+syscall has been executed asynchronously.
 
 All functions that expect a filehandle will also accept a file descriptor.