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NNTP-Posting-Date: Sat, 29 Apr 2017 08:57:52 -0500
From: Gareth Owen <gwowen@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: Is this code considered to transgress the signed overflow purism?
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Date: Sat, 29 Apr 2017 14:57:52 +0100
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Xref: csiph.com comp.lang.c:108733

Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:

> int buffsize = width * height; // uh oh. UB here, can't do that

If only * had some sort of inverse operation we could use to check
whether width*height > INT_MAX

Lets pretend theres an operator called \ that does
inverse-multiplication. Then we could write

if(width <= INT_MAX \ height) {
    // No UB!!
}

But without that operator, we're definitely stuck with casting
everything to doubles.