[libcxx-commits] [libcxx] [libcxx] Handle windows system error code mapping in std::error_code. (PR #93101)

[James Y Knight via libcxx-commits]

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@@ -35,7 +35,12 @@ int main(int, char**) {
   {
     const std::error_category& e_cat1 = std::system_category();
     std::error_condition e_cond       = e_cat1.default_error_condition(5);
+#ifdef _WIN32
+    // Windows' system error 5 is ERROR_ACCESS_DENIED, which maps to generic code permission_denied.
+    LIBCPP_ASSERT(e_cond.value() == static_cast<int>(std::errc::permission_denied));
+#else
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jyknight wrote:

Yep. `system_category::default_error_condition` is supposed to create an error_candition in generic_category (if possible), using the `system_category` value specified. There's no guarantee that `system_category` value 5 maps to `generic_category` value 5, but it did before.

https://github.com/llvm/llvm-project/pull/93101