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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: Safety of casting from 'long' to 'int'
Date: Wed, 13 May 2026 15:28:30 -0700
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Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:

> cross@spitfire.i.gajendra.net (Dan Cross) writes:
>
>> In article <86lddnlvtr.fsf@linuxsc.com>,
>> Tim Rentsch  <tr.17687@z991.linuxsc.com> wrote:
>
> [...]
>
>>> Starting in C99, any mention of interrupts and signal handlers was
>>> removed, along with the carveout.
>>
>> This is wrong.  Section 7.14 of C23 talks about signals and
>> signal handlers at length.
>
> Obviously, but that's clearly not what Tim meant.  His statement
> was not wrong in context.  (7.14 describes <signal.h>.  It's not
> plausible that Tim would think that had been removed.)
>
>> I never mentioned "interrupts" at all (traditionally, Unix
>> signals, which formed the basis for C signals, are not
>> interrputs in the conventional sense.  Modern systems will
>> sometimes make use of interprocessor-interrupts to hasten their
>> delivery, however).
>>
>> I think you are talking about _only_ the description of
>> `longjmp`.  I am actually talking about the standard considered
>> in total.  I only mentioned "non-nested" signal handler because
>> C90 was explicit in saying that that `longjmp` from a _nested_
>> signal handler was UB.
>
> Yes, Tim was clearly talking only about the descrition of longjmp.
> His statement wasn't wrong, just restricted to a certain context.
> C90's description of of longjmp includes a paragraph about interrupts
> and signals.  C99 removed that paragraph.

Right.  Thank you for clarifying.