what is the diffrence between sycl::context and pi_context?

[wangzy0327]

what is the diffrence between sycl::context and pi_context?

[AlexeySachkov]

Hi @wangzy0327, sycl::context is a class which is documented by the SYCL core and it should be used when you develop your SYCL/DPC++ applications.

pi_context is an internal opaque type which our implementation of SYCL RT uses. Our runtime is built on top of a portability layer which we call PI: Plugin Interface. It allows us to have a unified codebase at SYCL RT level, but use different low-level runtimes (like OpenCL, Level Zero, CUDA, etc.) to implement SYCL APIs.

So, SYCL RT provides an implementation of sycl::context, which uses pi_context under the hood as a context identifier and that pi_context is treated differently depending on which low-level runtime (or PI plugin, or SYCL backend) is being used.