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Date: Wed, 24 Jun 2020 17:25:45 +0200 From: "Kars Mulder" <kerneldev@...smulder.nl> To: "Greg Kroah-Hartman" <gregkh@...uxfoundation.org> Cc: "Pavel Machek" <pavel@....cz>, linux-kernel@...r.kernel.org, "Kai-Heng Feng" <kai.heng.feng@...onical.com> Subject: Re: Writing to a const pointer: is this supposed to happen? On Wednesday, June 24, 2020 15:10 CEST, Greg Kroah-Hartman wrote: > Have you hit any runtime issues with this code doing this? These > strings should be held in writable memory, right? Or do you see a > codepath where that is not the case? I haven't ran into any issues with it; I was just looking at the code as reference for a patch I'm working on. I initially assumed that casting a const pointer to non-const and writing to it would be undefined behaviour, but after reading through the C99 standard I can't find an unambiguous statement whether it is undefined behaviour even if the const pointer points to an object that was originally non-const (like char* -> const char* -> char* casts); it only says it is undefined behaviour if the object was defined with the const qualifier. I should probably stop bothering you with my newbie questions.
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