repeat macro define

[hao jiu]

Hi,

   I can't understand the repeat macro define, what's the special meaning.

They art at here line 336 and 337, the other two at line 343 344 inside the structure.

Thanks.

[Peter Shkenev]

Hello,

I suggest you removing duplicates and trying to compile minix.

Best regards,

Peter

пятница, 4 июня 2021 г. в 17:14:09 UTC+3, milk.d...@gmail.com:

[hao jiu]

Hi,

    I recompile with removing duplicates inside the structure. it seems all well at the end of output message, and get a img.

Peter Shkenev 在 2021年6月5日 星期六上午8:36:59 [UTC-7] 的信中寫道：

[Пётр Шкенев]

Hello,

Now you can try to actually run this image. Since this is a multiboot code, you need just to check if your image boots.

If so, that macro duplicates do nothing and you can disregard them.

Best regards,

Peter

пн, 7 июн. 2021 г., 11:46 hao jiu <milk.d...@gmail.com>:

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[Giovanni]

On 06/07/2021 10:46 AM, hao jiu wrote:

> I recompile with removing duplicates inside the structure. it seems all
> well at the end of output message, and get a img.

In C language macros have a global scope in the compilation unit and may
not be redefined. Compilers should generate an error if a macro is
redefined with different value unless the macro in undefined before the
new definition. Other generate a warning even if the value is the same.

You can remove duplicates without causing any problem.

Ciao
Giovanni

[Murray Smith]

Even if the macro is within a struct?

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[Giovanni]

On 06/07/2021 09:40 PM, Murray Smith wrote:

> Even if the macro is within a struct?

Yes it doesn't matter. They are still global to the scope of the
compilation unit.

Ciao
Giovanni
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[Пётр Шкенев]

Hello,

C macros are quite separate from C language itself. They are processed by, hm, preprocessor and are removed from output. So, basically speaking, macros don't have a clue about the rest of C (in fact, you can use macros in non-C files). Actual compiler, in its turn, doesn't see these macros.

Best regards,

Peter

вт, 8 июн. 2021 г., 12:01 'Giovanni' via minix3 <min...@googlegroups.com>:

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[stux...@gmail.com]

Although it won't be handled right away, if possible, a quick Pull request should be made to fix this duplicate definition issue.

For posterity, here is a permanent link to the commit and line in question (the copy is just below)

• https://github.com/Stichting-MINIX-Research-Foundation/minix/blob/4db99f4012570a577414fe2a43697b2f239b699e/minix/include/arch/earm/include/multiboot.h#L336
  

-stux