On Feb 9, 2020, at 2:29 AM, pd-dev-request@lists.iem.at wrote:

Message: 1
Date: Sun, 9 Feb 2020 02:29:49 +0100
From: Christof Ressi <info@christofressi.com>
To: pd-dev@lists.iem.at
Subject: Re: [PD-dev] Tips on debugging dip crashes?
Message-ID: <f1514d4a-dc01-cb71-f271-98e53ca7a629@christofressi.com>
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by applying a union used in one part of the code to another to 

replace a dereferencing cast

Type punning via pointer casts often violates the "strict aliasing 
rules" and the compiler might do wonky optimizations. Type punning via 
unions, on the other hand, is explicitly allowed in C. It is *not* 
allowed in C++, although in practice I haven't encountered a case where 
it didn't work. (The legal way to do type punning in C++ has been 
memcpy() , which gets fully optimized away; C++20 finally has 
std::bit_cast()).

You probably know this anyway. Just writing for other people who are 
reading :-)

Christof