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Re: Make THISFN simpler and more powerful [message #60924 is a reply to message #60923]

Tue, 08 October 2024 19:25

Didier
Messages: 732
Registered: November 2008
Location: France

Contributor

Hello Lance,

What compilers do with bit field is not covered by a standard and is implementation defined... so they do just about whatever they want.
BUT, something important is missing in you're code ! If you really want everything to be side by side, bit wise, you have to specify PACKED option on you're structs
search the web :

__attribute__((packed, aligned(X)))

__PACKED__

This will force the compiler to 'pack' all the bits together not waisting anything : so you will have a stable size.

Note : positionning of the inside the struct is implementation defined ... so some compilers put them in on order, and others the other way around Wink

==> you're code won't be very portable

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[Message index]

		Make THISFN simpler and more powerful By: Lance on Tue, 18 October 2022 21:08
		Re: Make THISFN simpler and more powerful By: Lance on Thu, 10 November 2022 00:32
		Re: Make THISFN simpler and more powerful By: Oblivion on Thu, 10 November 2022 06:29
		Re: Make THISFN simpler and more powerful By: Lance on Thu, 10 November 2022 12:52
		Re: Make THISFN simpler and more powerful By: Lance on Thu, 10 November 2022 21:41
		Re: Make THISFN simpler and more powerful By: Lance on Fri, 11 November 2022 02:50
		Re: Make THISFN simpler and more powerful By: Lance on Tue, 08 October 2024 18:38
		Re: Make THISFN simpler and more powerful By: Lance on Tue, 08 October 2024 18:42
		Re: Make THISFN simpler and more powerful By: Didier on Tue, 08 October 2024 19:25
		Re: Make THISFN simpler and more powerful By: Lance on Tue, 08 October 2024 20:01
		Re: Make THISFN simpler and more powerful By: Lance on Wed, 09 October 2024 05:59
		Re: Make THISFN simpler and more powerful By: Lance on Wed, 09 October 2024 16:09
		Re: Make THISFN simpler and more powerful By: Lance on Wed, 09 October 2024 16:17
		Re: Make THISFN simpler and more powerful By: Didier on Wed, 09 October 2024 19:32
		Re: Make THISFN simpler and more powerful By: Lance on Thu, 10 October 2024 14:01
		Re: Make THISFN simpler and more powerful By: Lance on Thu, 10 October 2024 14:06
		Re: Make THISFN simpler and more powerful By: Lance on Tue, 05 November 2024 02:25
		Re: Make THISFN simpler and more powerful By: Lance on Tue, 05 November 2024 02:33
		Re: Make THISFN simpler and more powerful By: Lance on Thu, 07 November 2024 00:49
		Re: Make THISFN simpler and more powerful By: Lance on Fri, 29 November 2024 02:30

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