Re: Unexplainable behaviour with direct struct assignment.
On Wednesday, 18 May 2022 at 21:49:14 UTC, HuskyNator wrote: After updating to `DMD 2.100.0` & `DUB 1.29.0`, I still get this behavior. Only when I use `dub run --b=debug` however (default for me). `dub run --b=release` does return what one would expect. I'm still on 2098.1, Windows 10 and get this at 64bit only ``` 9.18366e-40 50 nan ``` but no matter if debug build or not.
Re: Unexplainable behaviour with direct struct assignment.
On Thursday, 19 May 2022 at 04:33:01 UTC, Tejas wrote: Does this happen with LDC as well? I tried it using `LDC 1.29.0` and it prints correctly under both `--b=release` and `--b=debug` builds.
Re: Unexplainable behaviour with direct struct assignment.
On Wednesday, 18 May 2022 at 21:52:18 UTC, HuskyNator wrote: On Wednesday, 18 May 2022 at 21:49:14 UTC, HuskyNator wrote: After updating to `DMD 2.100.0` & `DUB 1.29.0`, I still get this behavior. Only when I use `dub run --b=debug` however (default for me). `dub run --b=release` does return what one would expect. I don't know if this matters either, but I'm using windows 10 (64 bits). Can confirm this is the case for me too on Windows 10. Release prints 50 3 times, debug prints 0, 50, nan. This is with DMD, I currently don't have LDC or GDC installed on this machine. So it looks like a Windows bug, critical at that.
Re: Unexplainable behaviour with direct struct assignment.
On Wednesday, 18 May 2022 at 21:52:18 UTC, HuskyNator wrote: On Wednesday, 18 May 2022 at 21:49:14 UTC, HuskyNator wrote: After updating to `DMD 2.100.0` & `DUB 1.29.0`, I still get this behavior. Only when I use `dub run --b=debug` however (default for me). `dub run --b=release` does return what one would expect. I don't know if this matters either, but I'm using windows 10 (64 bits). Does this happen with LDC as well?
Re: Unexplainable behaviour with direct struct assignment.
On Wednesday, 18 May 2022 at 21:49:14 UTC, HuskyNator wrote: After updating to `DMD 2.100.0` & `DUB 1.29.0`, I still get this behavior. Only when I use `dub run --b=debug` however (default for me). `dub run --b=release` does return what one would expect. I don't know if this matters either, but I'm using windows 10 (64 bits).
Re: Unexplainable behaviour with direct struct assignment.
On Wednesday, 18 May 2022 at 20:16:51 UTC, Dennis wrote: On Wednesday, 18 May 2022 at 20:05:05 UTC, HuskyNator wrote: This will print: ``` 0 50 nan ``` Which compiler and flags are you using? For me it just prints 50, you might be stumbling on some (old) bugs in the DMD backend with floating point registers. Examples of such bugs are: https://issues.dlang.org/show_bug.cgi?id=18573 https://issues.dlang.org/show_bug.cgi?id=22163 I've been using `DMD 2.098.0` using a default DUB (1.27.0) init project (I'm not quite sure what the compile flags are). After updating to `DMD 2.100.0` & `DUB 1.29.0`, I still get this behavior. Only when I use `dub run --b=debug` however (default for me). `dub run --b=release` does return what one would expect.
Re: Unexplainable behaviour with direct struct assignment.
On Wednesday, 18 May 2022 at 20:05:05 UTC, HuskyNator wrote: This will print: ``` 0 50 nan ``` Which compiler and flags are you using? For me it just prints 50, you might be stumbling on some (old) bugs in the DMD backend with floating point registers. Examples of such bugs are: https://issues.dlang.org/show_bug.cgi?id=18573 https://issues.dlang.org/show_bug.cgi?id=22163
Re: Unexplainable behaviour with direct struct assignment.
On Wed, May 18, 2022 at 08:05:05PM +, HuskyNator via Digitalmars-d-learn
wrote:
[...]
> ```d
> module app;
> import std.stdio;
>
> struct A {
> float[1] vec;
> this(float[1] n) {
> this.vec = n;
> }
> }
>
> void main(string[] args) {
> A c = A([50.0f]);
> writeln(c.vec[0]);
>
> A b = A([50.0f]);
> writeln(b.vec[0]);
>
> c = A([50.0f]);
> writeln(c.vec[0]);
> }
> ```
>
> This will print:
> ```
> 0
> 50
> nan
> ```
[...]
Can't replicate this problem. On my local machine (Linux/64), I get the
output:
50
50
50
What's the exact compile command you're using?
T
--
To err is human; to forgive is not our policy. -- Samuel Adler
Unexplainable behaviour with direct struct assignment.
I came across strange, seemingly non-deterministic, behaviour
today. I simplified it the best I could below. I entice you to
run the following piece of code.
```d
module app;
import std.stdio;
struct A {
float[1] vec;
this(float[1] n) {
this.vec = n;
}
}
void main(string[] args) {
A c = A([50.0f]);
writeln(c.vec[0]);
A b = A([50.0f]);
writeln(b.vec[0]);
c = A([50.0f]);
writeln(c.vec[0]);
}
```
This will print:
```
0
50
nan
```
My findings:
- The first initializer will always contain 0
- Initialization to another variable will yield the expected 50
- Reinitialization will always yield null
Am I missing something? Is this a bug? I have no idea what is
wrong.
Thanks for you help,
- HN
