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From: Patrick Herbst <paherbst@gmail.com>
Date: Mon, 30 Jan 2023 17:35:39 -0500
Message-ID: <CACMdL5+OX879q0Fhbuqd65P5_kL+zSwstKOX0FbYd_1-bFUWtg@mail.gmail.com>
Subject: how does -Wstringop-truncation work?
To: gcc-help <gcc-help@gcc.gnu.org>
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List-Id: <gcc-help.gcc.gnu.org>

I'm trying to understand how -Wstringop-truncation is generated.

I'm using the following example code with vanilla gcc 11.3 to generate
the warning

void append (char *buf, size_t bufsize)
{
  strncat (buf, ".txt", 3);
}

I can get the warning to display if running
gcc -Wall -02

I can even get it to display if running
gcc -Wall -O1 -foptimize-strlen

but i cannot get it to display if not using optimization.  I've even
tried manually adding all the -f options documented for -O1 to
understand what other flags might be needed to generate the warning.
I've had no success.

Is there a way to generate the -Wstringop-truncation warning without
optimization?