Messages in this thread | | | From | Linus Torvalds <> | Date | Sun, 28 Feb 2021 12:00:22 -0800 | Subject | Re: [PATCH 00/11] pragma once: treewide conversion |
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On Sun, Feb 28, 2021 at 11:34 AM Alexey Dobriyan <adobriyan@gmail.com> wrote: > > > > > End result: #pragma is fundamentally less reliable than the > > traditional #ifdef guard. The #ifdef guard works fine even if you > > re-read the file for whatever reason, while #pragma relies on some > > kind of magical behavior.
You continue to not even answer this very fundamental question.
"#pragma once" doesn't seem to have a _single_ actual real advantage.
Everybody already does the optimization of not even opening - much less reading and re-parsing - headers that have the traditional #ifdef guard.
And even if you _don't_ do that optimization, the #ifdef guard fundmentally semantically guarantyees the right behavior.
So the #ifdef guard is (a) standard (b) simple (c) reliable (d) traditional
and you have yet to explain a _single_ advantage of "#pragma once".
Why add this incredible churn that has no upside?
So no. We're not using #pragma once unless y9ou can come up with some very strong argument for it
And no, having to come up with a name for the #ifdef guard is not a strong argument. It's simply not that complicated.
Linus
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