| 27 Feb 2021 |
 agg | I guess if you're looking at the elf of the same executable it's fine :p | 13:13:54 |
 korken89 | Defined layout yes, just dumping memory no ;) | 13:14:02 |
| korken89 | Hehe indeed | 13:14:05 |
 gsalazar | so maybe I can elaborate a bit on the question: I am converting something from C and replicated a structure (which has attribute packed on the C code) to fill the different data that then I need to send via USB to the host | 13:15:40 |
| gsalazar | the host needs to receive the structure with the same information in the same order to interpret it correctly | 13:16:13 |
| gsalazar | and I was wondering on the best way to do so | 13:17:21 |
| agg | I've used eg slice::from_raw_parts as a slightly less dangerous transmute | 13:18:57 |
| agg | Be sure to put repr(c) and repr(packed) on the struct | 13:19:10 |
| agg | Then slice::from_raw_parts(&s as *const _, mem::size_of::<T>()) or something like that | 13:20:05 |
| agg | https://github.com/adamgreig/ffp/blob/master/firmware/src/hal/usb/packets.rs#L287 | 13:21:22 |
| korken89 | I found it quite interesting that even reading padding bytes in unpacked structures was well defined, even though they are considered uninitialised | 13:26:31 |
| korken89 | Interesting special case of uninitialised memory | 13:26:55 |
| agg | Yea, I was a bit surprised by that | 13:30:43 |
| agg | Not sure I knew about it when I wrote the comment in that file | 13:30:52 |
| korken89 | I find it weird and cool | 13:32:20 |
| korken89 | But makes sense, else memcpy would be UB | 13:32:39 |
| gsalazar | agg korken89: thanks | 15:18:56 |
 bradleyharden | Is there any way to do pointer arithmetic in the declaration of a const? I want to declare a constant that is a pointer to a field of a PAC RegisterBlock. I can call the PAC struct's ::ptr() method to get a pointer to the block, but I can't dereference the pointer in a const expression. I can't cast the pointer to uszie, because that's unsatable. And I can't use .offset(), .add() and the like, because they aren't constant functions. | 15:22:49 |
| bradleyharden | * Is there any way to do pointer arithmetic in the declaration of a const? I want to declare a constant that is a pointer to a field of a PAC RegisterBlock. I can call the PAC struct's ::ptr() method to get a pointer to the block, but I can't dereference the pointer in a const expression. I can't cast the pointer to uszie, because that's unsatable. And I can't use .offset(), .add() and the like, because they aren't constant functions. | 15:25:19 |
| bradleyharden | I guess I can use the literal address and then cast to a pointer. But that's brittle. | 15:26:47 |
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 yatekii | Does anyone know if there is a way to detect the macOS version from within cargo/rustc? ^^ | 16:58:28 |
| yatekii | (have a dependency depend on it) | 16:58:36 |
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