From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jonathan Nieder <jrnieder@gmail.com>
Subject: OT: typesafe callbacks in C (Re: [WIP PATCH 1/7] Add skeleton RA
 svnclient)
Date: Fri, 25 Jun 2010 10:30:32 -0500
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Cc: Ramkumar Ramachandra <artagnon@gmail.com>,
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To: Daniel Shahaf <d.s@daniel.shahaf.name>
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Daniel Shahaf wrote:

> By the way, a common pitfall is to mis-treat the void *baton argument as
> the wrong type of baton.  That is, code of the form
> 
>     f(void *baton) {
>         foo_baton_t *fb = baton;
>     }
> 
> instead of
> 
>     f(void *baton) {
>         bar_baton_t *bb = baton;
>     }

Just for kicks, I should mention

  http://ccan.ozlabs.org/info/typesafe_cb.html

which makes code like this cause warnings with gcc.

Maybe some version of Subversion years from now could use it.