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denoland-deno/cli/napi_sym/README.md
Luke Channings fa22956a86
refactor(build): better handle old glibc (#16238)
Follow-up to #16208.

- Refactors build.rs behaviour to use `-exported_symbols_list` /
`--export-dynamic-symbol-list`
- Since all build systems now rely on a symbols list file, I have added
`generate_exported_symbols_list`, which derives the symbol list file
depending on the platform, which makes `tools/napi/generate_link_win.js`
redundant.
- Fixes a missed instance of `i8` being used instead of `c_char`

Co-authored-by: Divy Srivastava <dj.srivastava23@gmail.com>
2022-10-15 20:51:04 +05:30

1,020 B

napi_sym

A proc_macro for Deno's Node-API implementation. It does the following things:

  • Marks the symbol as #[no_mangle] and rewrites it as pub extern "C" $name.
  • Asserts that the function symbol is present in symbol_exports.json.
  • Maps deno_napi::Result to raw napi_result.
use deno_napi::{napi_value, Env, Error, Result};

#[napi_sym::napi_sym]
fn napi_get_boolean(
  env: *mut Env,
  value: bool,
  result: *mut napi_value,
) -> Result {
  let _env: &mut Env = env.as_mut().ok_or(Error::InvalidArg)?;
  // *result = ...
  Ok(())
}

symbol_exports.json

A file containing the symbols that need to be put into the executable's dynamic symbol table at link-time.

This is done using /DEF: on Windows, -exported_symbol,_ on macOS and --export-dynamic-symbol= on Linux. See cli/build.rs.

On Windows, you need to generate the .def file by running tools/napi/generate_symbols_lists.js.