Ship hosting layer error codes as a public header

[elinor-fung]

Ships the hosting StatusCode enum as a public host_error_codes.h header (alongside nethost.h and hostfxr.h) so native host consumers no longer need to manually redefine the error/exit codes returned by the hostfxr, hostpolicy, and nethost APIs. The header is packaged in the Microsoft.NETCore.DotNetAppHost package and is validated to compile as pure C.

Resolves #110891

cc @dotnet/appmodel @AaronRobinsonMSFT

Note

This pull request was authored with the assistance of GitHub Copilot.

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[Copilot]

Pull request overview

This PR makes the host-layer StatusCode values available as a shipped public C header by installing src/native/corehost/error_codes.h as host_error_codes.h alongside other hosting headers and ensuring it can be included from pure C code.

Changes:

• Install and package error_codes.h as host_error_codes.h (for nethost/apphost consumers).
• Update packaging projects to include the new header in the output artifacts.
• Extend the pure-C header inclusion test to include error_codes.h.

Show a summary per file

File	Description
src/native/corehost/test/mockhostfxr/test_c_api.c	Adds error_codes.h to the pure-C include validation test.
src/native/corehost/nethost/CMakeLists.txt	Installs error_codes.h under the public name host_error_codes.h.
src/native/corehost/error_codes.h	Wraps the C++-only static_cast macro usage to keep the header C-compatible.
src/installer/pkg/projects/Microsoft.NETCore.DotNetAppHost/Microsoft.NETCore.DotNetAppHost.pkgproj	Adds host_error_codes.h to the DotNetAppHost package contents.
src/installer/pkg/archives/dotnet-nethost.proj	Publishes host_error_codes.h into the dotnet-nethost archive output.

Copilot's findings

• Files reviewed: 5/5 changed files
• Comments generated: 2

[Copilot]

Copilot's findings

Comments suppressed due to low confidence (1)

src/native/corehost/error_codes.h:59

• STATUS_CODE_SUCCEEDED is now only defined for C++, which means C consumers (the stated target for this header) can't use the convenience macro at all. Since the goal is a header that works as pure C, consider providing a C-compatible definition under #else (using enum StatusCode + C-style casts) rather than omitting the macro entirely.

#ifdef __cplusplus
#define STATUS_CODE_SUCCEEDED(status_code) ((static_cast<int>(static_cast<StatusCode>(status_code))) >= 0)
#else

• Files reviewed: 6/6 changed files
• Comments generated: 0 new

[Copilot]

Copilot's findings

Comments suppressed due to low confidence (1)

src/native/corehost/error_codes.h:61

• This header is now being shipped publicly as host_error_codes.h (via CMake install/package). The include guard __ERROR_CODES_H__ is both very generic and uses a reserved identifier form (leading __), which increases collision risk for consumers and is technically undefined-behavior territory in public headers. Consider switching to a unique, non-reserved guard name (e.g., HAVE_HOST_ERROR_CODES_H to match other public hosting headers) and update the trailing #endif comment accordingly.

#ifdef __cplusplus
#define STATUS_CODE_SUCCEEDED(status_code) ((static_cast<int>(static_cast<StatusCode>(status_code))) >= 0)
#else
#define STATUS_CODE_SUCCEEDED(status_code) (((int)(status_code)) >= 0)
#endif // __cplusplus

• Files reviewed: 6/6 changed files
• Comments generated: 0 new

[Copilot]

Copilot's findings

Comments suppressed due to low confidence (2)

src/installer/pkg/projects/Microsoft.NETCore.DotNetAppHost/Microsoft.NETCore.DotNetAppHost.pkgproj:13

• This NativeBinary header list appears to be kept in filename order (coreclr_delegates.h, host*, nethost.h). Adding host_error_codes.h after hostfxr.h breaks that ordering; please keep the list sorted to reduce churn in future diffs.

    <NativeBinary Include="$(DotNetHostBinDir)/coreclr_delegates.h" />
    <NativeBinary Include="$(DotNetHostBinDir)/hostfxr.h" />
    <NativeBinary Include="$(DotNetHostBinDir)/host_error_codes.h" />
    <NativeBinary Include="$(DotNetHostBinDir)/nethost.h" />

src/native/corehost/error_codes.h:57

• STATUS_CODE_SUCCEEDED relies on casting to int and comparing >= 0. Since the StatusCode enum contains values larger than INT_MAX, the enum’s underlying type can become unsigned and the signed conversion is implementation-defined. For a public C header, it’s safer to check the high bit directly, while keeping static_cast for C++ builds.

#define STATUS_CODE_SUCCEEDED(status_code) (((int)(status_code)) >= 0)

• Files reviewed: 6/6 changed files
• Comments generated: 0 new

[elinor-fung]

/ba-g dead-letter in unrelated wasm leg