Re: RFC: Serial port DTR/RTS - O_<something>
From: Ned Ulbricht <hidden>
Date: 2025-11-15 21:39:11
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On 11/14/25 10:53, H. Peter Anvin wrote:
On November 14, 2025 10:49:09 AM PST, "Maciej W. Rozycki" [off-list ref] wrote:quoted
On Thu, 13 Nov 2025, H. Peter Anvin wrote:quoted
quoted
I think this is going to be the most difficult. I don't remember why I rejected the old submission, but maybe it would have modified the existing behaviour? A new open flag "O_DO_NOT_TOUCH_ANYTHING" might be the simplest?Okay, to I'm going to toss out a couple suggestions for naming: O_(PRE|FOR|N|NO)?(INIT|CONFIG|START)(DEV|HW|IO)? O_(NO?RESET|PREPARE)(DEV|HW|IO)? O_NO?TOUCH O_NYET ("not yet") I think my personal preference at the moment is either O_NYET or O_PRECONFIG or O_NYET; although it is perhaps a bit more "use case centric" than "what actual effect it has" I think it might be clearer. A -DEV, -HW or -IO suffix would seem to needlessly preclude it being used for future similar use cases for files that are not device nodes.Hmm, I'm inconvinced about any of these. How about O_FDONLY, to reflect that you are after a file descriptor only [snip]
Hi all, Resurrecting a (private email) discussion from a few years back now, my personal preferences are: (1) O_KEEP (2) O_TTY_KEEP (3) O_TTY_NOINIT. (Of course, naming an open() flag has got to be a paradigmatic invitation for bike-shedding...) It's worth pointing out, though, that even though O_TTY_INIT doesn't generally appear in linux headers, that particular flag is documented in POSIX to have at least incompatible --perhaps even strictly opposite-- behavior compared with this new proposed flag. See The Open Group Base Specifications Issue 8 (IEEE Std 1003.1-2024): | 11.1.1 Opening a Terminal Device File | | 3. ... The terminal parameters can be set to values that ensure the | terminal behaves in a conforming manner by means of the O_TTY_INIT | open flag.... https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap11.html | open, openat — open file | | O_TTY_INIT https://pubs.opengroup.org/onlinepubs/9799919799/ That's what motivates my first-glance preference to name this new flag, which will have approximately opposite behavior, as O_TTY_NOINIT. But as a generic abstraction, I more prefer O_KEEP. Ned