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From: Andy Burns <usenet@andyburns.uk>
Newsgroups: comp.sys.raspberry-pi
Subject: Re: Fscking Pointers.
Date: Wed, 26 Mar 2025 20:08:42 +0000
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The Natural Philosopher wrote:

> It seems C has caught the disease of 'we will modify your code according 
> to what WE think it means'..
> 
> ..my pointers to 254 byte structures are going haywire when I add 256 
> bytes to them...I have to add one instead...

if C knows the thing being pointed to is a 254 byte struct, then adding 
256 to it will move it by 65024 bytes surely?


adding 1, will move it by 254 bytes.


> ..add that to the fact that to write to flash RAM you need to specify 
> the *offset* from flash RAM base, but to read it you need to use the 
> actual hardware address...

are you casting pointers?

> sigh.
> 
> What is the generic type for a simple pointer to presumably bytes, in 
> ARM C?

traditionally char*

> Or should I resign myself to doing everything in 256byte chunks? the 
> structure to be read and written from Flash  is exactly that big for 
> obvious hardware reasons...