Exception in SYCL

Errors, what we hate but can't avoid. If you ever tried to debug an OpenCL program, you know how painful it is. However, SYCL offers C++ exception handling for host code, which is a bit of a blessing.

Parallel computation device don't have exception mechanism because it impedes the parallelism.

Synchronous Exceptions

Synchronous exceptions are identical to the standard C++ exception, just of type sycl::exception.

Asynchronous Exceptions

Asynchronous Exceptions are exceptions thrown within the host task in the action graph.

You need a handler to deal with that- and that's it.

#include <sycl/sycl.hpp>
using namespace sycl;

// Our example asynchronous handler function
auto handle_async_error = [](exception_list elist) {
    for (auto &e : elist) {
        try {
            std::rethrow_exception(e);
        } catch (...) {
            std::cout << "Caught SYCL ASYNC exception!!\n";
        }
    }
};

void say_device(const queue &Q) {
    std::cout << "Device : "
              << Q.get_device().get_info<info::device::name>()
              << "\n";
}

class something_went_wrong {}; // Example exception type

int main() {
    queue q{cpu_selector_v, handle_async_error};
    say_device(q);

    q.submit([&](handler &h) {
        h.host_task([&]() { throw something_went_wrong{}; });
    }).wait();

    return 0;
}