I am receiving this error:

Error: no property `offsetof` for type `char*`

from this snippet:

import core.sys.windows.setupapi;

void main() {
    SP_DEVICE_INTERFACE_DETAIL_DATA_A DeviceInterfaceDetail;
    uint Offset = DeviceInterfaceDetail.DevicePath.offsetof;
}

You may try this at https://run.dlang.io/, build with LDC, with argument: -mtriple=x86_64-windows-msvc.

It's a method returning a CHAR* - _DevicePath is the actual member. I guess it's a dynamically sized struct, which cannot be mapped directly to D, hence this representation.

Thank you, that seems to have resolved the issue, though I wish these sorts of problems would stop cropping up, they are souring the experience with the language.

On 8/19/22 9:49 AM, MyNameHere wrote:

Most likely that "member" is a macro in C. D doesn't have macros, so it uses properties.

The error message could be better though.

-Steve

On Friday, 19 August 2022 at 14:22:04 UTC, Steven Schveighoffer wrote:

Nope, it's really a dynamically sized struct with a last CHAR[1] member: https://docs.microsoft.com/en-us/windows/win32/api/setupapi/ns-setupapi-sp_device_interface_detail_data_a

Just like with C, these abominations need very special care, and regularly allocating on the stack or using as an aggregate field isn't possible.

On Friday, 19 August 2022 at 13:49:08 UTC, MyNameHere wrote:

Oh and DevicePath() is a convenience member returning a pointer to the 'dynamic array' (as the array decays to a pointer in C too), so no need to fiddle with .offsetof and computing the pointer manually.

On Friday, 19 August 2022 at 14:30:50 UTC, kinke wrote:

I am using -BetterC, so that path is closed to me, I think.

On 8/19/22 12:36 PM, MyNameHere wrote:

dynamic arrays are really slices, and they are allowed in betterC.

-Steve

On Friday, 19 August 2022 at 16:36:24 UTC, MyNameHere wrote:

I believe you aren't allowed to append to dynamic arrays/slices; otherwise you can use them