#pragma is a compiler-specific and even #pragma once is implement by all
major compilers, still it is not a standard way to go. so by preserving
the pp-token once for usage by #include it will become reliable that any
compiler will implement will implement it and this way we will rely on a
standard behavior rather than a compiler-specific once. that what I mean
by "safer".


------ Original Message ------
>From "Andre Kostur" <andre_at_[hidden]>
To std-proposals_at_[hidden]
Cc "Muhammad" <mail_at_[hidden]>
Date 3/23/2025 6:19:03 AM
Subject Re: [std-proposals] #pragma once safer alternative

>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)
>># include < h-char-sequence > new-line
>># include " h-char-sequence " new-line
>># 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
>>
>># include < h-char-sequence > new-line
>># include " h-char-sequence " new-line
>># include once new-line
>># 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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>>Std-Proposals_at_[hidden]
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