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Summary:
Decorate the public hermes_napi entry points (hermes_napi_create_env,
hermes_napi_get_last_registered_module, hermes_napi_load_module,
hermes_run_script, hermes_run_bytecode) with NAPI_EXTERN and NAPI_CDECL,
matching the canonical declaration style used throughout js_native_api.h.
NAPI_EXTERN expands to visibility("default") on non-Windows, so without
it these symbols could be hidden when the library is built with
-fvisibility=hidden, leaving the entry points unexported. NAPI_CDECL
fixes the calling convention on Windows. The macros are already in scope
via the existing node_api.h include, and the attribute carries to the
definitions in hermes_napi.cpp since the header is transitively included
there.
Differential Revision: D107462337
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This was referenced Jul 13, 2026
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Summary: The public `hermes_napi_*` / `hermes_run_*` entry points in `API/napi/hermes_napi.h` are decorated with `NAPI_EXTERN NAPI_CDECL` (added in #2044), where `NAPI_EXTERN` expands to `__attribute__((visibility("default")))` on non-Windows. However, unlike the sibling headers `js_native_api.h` and `node_api.h`, `hermes_napi.h` does not wrap its declarations in `extern "C"`, so these functions get C++ linkage. With C++ linkage the symbols are name-mangled and are not exported from a library built with `-fvisibility=hidden` (the root `CMakeLists.txt` appends this globally). Consumers linking the resulting shared library therefore hit undefined symbols such as `hermes_napi_create_env`, while the `extern "C"` symbols from `js_native_api.h` / `node_api.h` export as expected. This wraps the declarations in `EXTERN_C_START` / `EXTERN_C_END` — the same macros used by the sibling headers, already in scope via the `node_api.h` include — so `NAPI_EXTERN`'s `visibility("default")` takes effect and the entry points are exported. These are a C API (a Hermes extension of the C Node-API), so `extern "C"` is the correct linkage on its own merits. This is the natural follow-up to #2044, which intended to export these symbols. Note: this changes the exported symbols from mangled C++ names to their C names (e.g. `hermes_napi_create_env`). The `= nullptr` default argument on `hermes_napi_create_env` is a call-site feature and is compatible with `extern "C"` linkage. Pull Request resolved: #2106 Test Plan: - [ ] Build with default flags and confirm `hermes_napi_create_env` and the other entry points appear in the exported symbol table of the built shared library. Reviewed By: tmikov Differential Revision: D112358086 Pulled By: avp fbshipit-source-id: 690f5e1e3ea2b4a59c478b8393f82ab138f348d9
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Summary:
Decorate the public hermes_napi entry points (hermes_napi_create_env,
hermes_napi_get_last_registered_module, hermes_napi_load_module,
hermes_run_script, hermes_run_bytecode) with NAPI_EXTERN and NAPI_CDECL,
matching the canonical declaration style used throughout js_native_api.h.
NAPI_EXTERN expands to visibility("default") on non-Windows, so without
it these symbols could be hidden when the library is built with
-fvisibility=hidden, leaving the entry points unexported. NAPI_CDECL
fixes the calling convention on Windows. The macros are already in scope
via the existing node_api.h include, and the attribute carries to the
definitions in hermes_napi.cpp since the header is transitively included
there.
Differential Revision: D107462337