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Date: Thu, 26 Feb 2026 09:17:24 +0000 (UTC)
To: KENNON J CONRAD <kennonconrad AT comcast DOT net>,
        Glenn Strauss <gs-cygwin DOT com AT gluelogic DOT com>
Cc: KENNON J CONRAD via Cygwin <cygwin AT cygwin DOT com>
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Subject: Re: Memmove causing program crashes, giving SIGTRAP in GDB(?)
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From: matthew patton via Cygwin <cygwin AT cygwin DOT com>
Reply-To: matthew patton <pattonme AT yahoo DOT com>
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On Wed, Feb 25, 2026 at 11:59:07PM -0800, KENNON J CONRAD via Cygwin wrote:
> Okay, so now I learned about setting the frame and disassemble and see the memmove code:
> 
> Dump of assembler code for function memmove:
[snip]
> => 0x00007ff96ba812a9 <+137>:    rep movsq %ds:(%rsi),%es:(%rdi)
[snip]
> End of assembler dump.

movsq requires address alignment of 8 bytes.
What are the pointer addresses of the arguments to memmove()?
A SIGTRAP may result if the addresses are not 8-byte aligned.


767 * 2 / 8 and 2633 * 2 / 8 would seem to violate that rule.


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