• Selim Ozel (14/14) Jul 28 2021 import std.conv:to;
• Paul Backus (8/20) Jul 28 2021 The reason `std.conv.to` doesn't work in `@nogc` is that it
• Kagamin (11/11) Jul 29 2021 I use this:
• Selim Ozel (1/1) Jul 29 2021 Great answers, thanks :)
• Rumbu (11/25) Jul 29 2021 Length property of arrays is architecture dependent returning
• Selim Ozel (5/34) Aug 16 2021 Thank you. I'll try this one as well. The conversion suggested

Selim Ozel <sozel wpi.edu> writes:

import std.conv:to;

```d
import std.conv:to;

 nogc int
myFunction(ulong number){
return to!int(number);
}
```

Since std.conv.to is a non nogc myFunction throws a compiler 
error. From a practical perspective length property of arrays 
return ulong. What do you think is a reasonable way of casting 
that into int with no-gc.

Thanks,
Selim

Paul Backus <snarwin gmail.com> writes:

On Wednesday, 28 July 2021 at 17:41:04 UTC, Selim Ozel wrote:
 import std.conv:to;

 ```d
 import std.conv:to;

  nogc int
 myFunction(ulong number){
 return to!int(number);
 }
 ```

 Since std.conv.to is a non nogc myFunction throws a compiler 
 error. From a practical perspective length property of arrays 
 return ulong. What do you think is a reasonable way of casting 
 that into int with no-gc.

The reason `std.conv.to` doesn't work in ` nogc` is that it 
throws an exception when the conversion fails, and exceptions 
require the GC.

If you're ok with values larger than `int.max` causing overflow, 
you can just use `cast(int) number`. Otherwise, you will probably 
want to write your own conversion function that does overflow 
checking.

Kagamin <spam here.lot> writes:

I use this:

int ToInt(in ulong u) pure
{
	assert(u<=int.max);
	return cast(int)u;
}
int Count(E)(in E[] arr) pure
{
	return ToInt(arr.length);
}

Well, it depends if you're fine with just an assert.

Selim Ozel <sozel wpi.edu> writes:

Great answers, thanks :)

Rumbu <rumbu rumbu.ro> writes:

On Wednesday, 28 July 2021 at 17:41:04 UTC, Selim Ozel wrote:
 import std.conv:to;

 ```d
 import std.conv:to;

  nogc int
 myFunction(ulong number){
 return to!int(number);
 }
 ```

 Since std.conv.to is a non nogc myFunction throws a compiler 
 error. From a practical perspective length property of arrays 
 return ulong. What do you think is a reasonable way of casting 
 that into int with no-gc.

 Thanks,
 Selim

Length property of arrays is architecture dependent returning 
ulong for 64 bit and uint for 32 bit. You can use size_t as data 
type to cover both cases.

Therefore your function can be portable without any conversion:

```d
 nogc size_t
myFunction(size_t number) {
return number;
}
```

Selim Ozel <sozel wpi.edu> writes:

On Friday, 30 July 2021 at 05:20:37 UTC, Rumbu wrote:
 On Wednesday, 28 July 2021 at 17:41:04 UTC, Selim Ozel wrote:
 import std.conv:to;

 ```d
 import std.conv:to;

  nogc int
 myFunction(ulong number){
 return to!int(number);
 }
 ```

 Since std.conv.to is a non nogc myFunction throws a compiler 
 error. From a practical perspective length property of arrays 
 return ulong. What do you think is a reasonable way of casting 
 that into int with no-gc.

 Thanks,
 Selim

 Length property of arrays is architecture dependent returning 
 ulong for 64 bit and uint for 32 bit. You can use size_t as 
 data type to cover both cases.

 Therefore your function can be portable without any conversion:

 ```d
  nogc size_t
 myFunction(size_t number) {
 return number;
 }
 ```

Thank you. I'll try this one as well. The conversion suggested 
above worked fine for my purposes but it does look a bit ugly :) 
I was not aware of the option to use soze_t.

S