DirectXShaderCompiler Support built-in offsetof macro

We should consider supporting offsetof in the future. Since this normally requires stddef.h/cstddef, we should consider adding built-in version under hlsl namespace with default/auto using namespace hlsl; when compiling hlsl source.

Separating this issue from the sizeof issue #1291 to allow independent resolution.

May 10 '19 20:05 tex3d

Offsetof is a macro in C/C++ and it's not expressible as a normal function, so I'm not sure it could even live in a namespace.

May 10 '19 21:05 tristanlabelle

I'm going to give up ownership of this issue as I'm not actively working on it.

Jun 16 '20 21:06 ehsannas

With the new addition of templated loads in ByteAddressBuffer this would be a huge win 😊

Dec 02 '20 17:12 Jasper-Bekkers

Came looking for this so I guess +1 from me, for the same reason Jasper listed.

Apr 23 '21 14:04 alextardif-zmi

Hi! Are there any news, by any chance? :) I've tried it on a recent build from the main branch, and the error I'm getting from

offsetof(SimpleStruct, uintValue)

says 'SimpleStruct' does not refer to a value, so it looks like the macro itself is recognized by dxc, but still doesn't work?

Nov 24 '21 12:11 curldivergence

+1, would love to have this :)

Apr 05 '22 20:04 jshopf

Is there any update? In sight of RWStructuredBuffers not beeing supported in array bindings for spirv output, the only real alternative is RWByteAdressBuffer for vulkan users in a bindless model. Without offsetof writing and reading individual fields of a struct becomes very error prone and ugly, as one needs to define the offsets to struct members manually.