How is this any “safer” than #pragma once? What does “safer” mean in this
context?

On Sat, Mar 22, 2025 at 21:16 Muhammad via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> The #include syntax (from cppreference.com)
>
> 1. # include < h-char-sequence > new-line
> 2. # include " h-char-sequence " new-line
> 3. # include pp-tokens new-line
>
> The pp-tokens in (3) is a macro that get expanded until it matches (1) or
> (2), and when it doesn't it is undefined behavior.
>
> This proposal is to add another syntax for #include
>
>
> 1. # include < h-char-sequence > new-line
> 2. # include " h-char-sequence " new-line
> 3. # include once new-line
> 4. # include pp-tokens new-line
>
>
> The fact that by convention all macros are written in all uppercase pr
> starts with underscore make this proposal very unlikely to break existing
> code.
>
> The implementation for this proposal is already done using the
> compiler-specific #pragma once syntax but here it will be more convenient
> and a standard way to not include it more than once.
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