diff --git a/pkgs/hooks/example/build/native_add_library/constants-ffigen.yaml b/pkgs/hooks/example/build/native_add_library/constants-ffigen.yaml
new file mode 100644
index 0000000000..f13e8aa75b
--- /dev/null
+++ b/pkgs/hooks/example/build/native_add_library/constants-ffigen.yaml
@@ -0,0 +1,31 @@
+# Run with `flutter pub run ffigen --config ffigen.yaml`.
+name: NativeAddBindings
+description: |
+  Bindings for `src/native_add_library.h`.
+
+  Regenerate bindings with `flutter pub run ffigen --config ffigen.yaml`.
+output: 'lib/src/constant_bindings.dart'
+headers:
+  entry-points:
+    - 'src/constants.g.h'
+
+  include-directives:
+    - 'src/constants.g.h'
+preamble: |
+  // Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+  // for details. All rights reserved. Use of this source code is governed by a
+  // BSD-style license that can be found in the LICENSE file.
+comments:
+  style: any
+  length: full
+ffi-native:
+
+structs:
+  rename:
+    'my_(.*)': '$1'
+functions:
+  rename:
+    'my_(.*)': '$1'
+typedefs:
+  rename:
+    'my_(.*)': '$1'
diff --git a/pkgs/hooks/example/build/native_add_library/constants.json b/pkgs/hooks/example/build/native_add_library/constants.json
new file mode 100644
index 0000000000..c765c52e92
--- /dev/null
+++ b/pkgs/hooks/example/build/native_add_library/constants.json
@@ -0,0 +1,32 @@
+[
+    "S_IEXEC",
+    "S_IFBLK",
+    "S_IFCHR",
+    "S_IFDIR",
+    "S_IFIFO",
+    "S_IFLNK",
+    "S_IFMT",
+    "S_IFREG",
+    "S_IFSOCK",
+    "S_IFWHT",
+    "S_IREAD",
+    "S_IRGRP",
+    "S_IROTH",
+    "S_IRUSR",
+    "S_IRWXG",
+    "S_IRWXO",
+    "S_IRWXU",
+    "S_ISGID",
+    "S_ISTXT",
+    "S_ISUID",
+    "S_ISVTX",
+    "S_IWGRP",
+    "S_IWOTH",
+    "S_IWRITE",
+    "S_IWUSR",
+    "S_IXGRP",
+    "S_IXOTH",
+    "S_IXUSR",
+    "UF_APPEND",
+    "UF_HIDDEN"
+]
\ No newline at end of file
diff --git a/pkgs/hooks/example/build/native_add_library/ffigen.yaml b/pkgs/hooks/example/build/native_add_library/ffigen.yaml
index 11e58af753..13a8713e68 100644
--- a/pkgs/hooks/example/build/native_add_library/ffigen.yaml
+++ b/pkgs/hooks/example/build/native_add_library/ffigen.yaml
@@ -4,10 +4,11 @@ description: |
   Bindings for `src/native_add_library.h`.
 
   Regenerate bindings with `flutter pub run ffigen --config ffigen.yaml`.
-output: 'lib/native_add_library.dart'
+output: 'lib/src/libc_bindings.dart'
 headers:
   entry-points:
     - 'src/native_add_library.h'
+
   include-directives:
     - 'src/native_add_library.h'
 preamble: |
@@ -18,3 +19,13 @@ comments:
   style: any
   length: full
 ffi-native:
+
+structs:
+  rename:
+    'my_(.*)': '$1'
+functions:
+  rename:
+    'my_(.*)': '$1'
+typedefs:
+  rename:
+    'my_(.*)': '$1'
diff --git a/pkgs/hooks/example/build/native_add_library/hook/build.dart b/pkgs/hooks/example/build/native_add_library/hook/build.dart
index 0ff9ad95e4..80cc6ff83f 100644
--- a/pkgs/hooks/example/build/native_add_library/hook/build.dart
+++ b/pkgs/hooks/example/build/native_add_library/hook/build.dart
@@ -11,8 +11,9 @@ void main(List<String> args) async {
     final packageName = input.packageName;
     final cbuilder = CBuilder.library(
       name: packageName,
-      assetName: '$packageName.dart',
-      sources: ['src/$packageName.c'],
+      assetName: 'src/libc_bindings.dart',
+      sources: ['src/$packageName.c', 'src/constants.g.c'],
+      flags: ['-Weverything'],
     );
     await cbuilder.run(
       input: input,
diff --git a/pkgs/hooks/example/build/native_add_library/lib/native_add_library.dart b/pkgs/hooks/example/build/native_add_library/lib/native_add_library.dart
index 419f8b03f6..106183a05b 100644
--- a/pkgs/hooks/example/build/native_add_library/lib/native_add_library.dart
+++ b/pkgs/hooks/example/build/native_add_library/lib/native_add_library.dart
@@ -1,12 +1,7 @@
-// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
+import 'src/libc_bindings.dart' as libc;
 
-// AUTO GENERATED FILE, DO NOT EDIT.
-//
-// Generated by `package:ffigen`.
-// ignore_for_file: type=lint
-import 'dart:ffi' as ffi;
+export 'src/constants.g.dart';
+export 'src/libc_bindings.dart' hide errno, seterrno;
 
-@ffi.Native<ffi.Int32 Function(ffi.Int32, ffi.Int32)>()
-external int add(int a, int b);
+int get errno => libc.errno();
+set errno(int err) => libc.seterrno(err);
diff --git a/pkgs/hooks/example/build/native_add_library/lib/src/constant_bindings.dart b/pkgs/hooks/example/build/native_add_library/lib/src/constant_bindings.dart
new file mode 100644
index 0000000000..c51b41425d
--- /dev/null
+++ b/pkgs/hooks/example/build/native_add_library/lib/src/constant_bindings.dart
@@ -0,0 +1,101 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// AUTO GENERATED FILE, DO NOT EDIT.
+//
+// Generated by `package:ffigen`.
+// ignore_for_file: type=lint
+import 'dart:ffi' as ffi;
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IEXEC')
+external int get_S_IEXEC();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IFBLK')
+external int get_S_IFBLK();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IFCHR')
+external int get_S_IFCHR();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IFDIR')
+external int get_S_IFDIR();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IFIFO')
+external int get_S_IFIFO();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IFLNK')
+external int get_S_IFLNK();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IFMT')
+external int get_S_IFMT();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IFREG')
+external int get_S_IFREG();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IFSOCK')
+external int get_S_IFSOCK();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IFWHT')
+external int get_S_IFWHT();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IREAD')
+external int get_S_IREAD();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IRGRP')
+external int get_S_IRGRP();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IROTH')
+external int get_S_IROTH();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IRUSR')
+external int get_S_IRUSR();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IRWXG')
+external int get_S_IRWXG();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IRWXO')
+external int get_S_IRWXO();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IRWXU')
+external int get_S_IRWXU();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_ISGID')
+external int get_S_ISGID();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_ISTXT')
+external int get_S_ISTXT();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_ISUID')
+external int get_S_ISUID();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_ISVTX')
+external int get_S_ISVTX();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IWGRP')
+external int get_S_IWGRP();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IWOTH')
+external int get_S_IWOTH();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IWRITE')
+external int get_S_IWRITE();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IWUSR')
+external int get_S_IWUSR();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IXGRP')
+external int get_S_IXGRP();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IXOTH')
+external int get_S_IXOTH();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_S_IXUSR')
+external int get_S_IXUSR();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_UF_APPEND')
+external int get_UF_APPEND();
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_get_UF_HIDDEN')
+external int get_UF_HIDDEN();
+
+const int my_UNDEFINED = 9223372036854775807;
diff --git a/pkgs/hooks/example/build/native_add_library/lib/src/constants.g.dart b/pkgs/hooks/example/build/native_add_library/lib/src/constants.g.dart
new file mode 100644
index 0000000000..f2b8efb257
--- /dev/null
+++ b/pkgs/hooks/example/build/native_add_library/lib/src/constants.g.dart
@@ -0,0 +1,273 @@
+// ignore_for_file: non_constant_identifier_names
+
+import 'constant_bindings.dart';
+int get S_IEXEC {
+  final v = get_S_IEXEC();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IEXEC');
+  } else {
+    return v;
+  }
+}
+
+int get S_IFBLK {
+  final v = get_S_IFBLK();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IFBLK');
+  } else {
+    return v;
+  }
+}
+
+int get S_IFCHR {
+  final v = get_S_IFCHR();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IFCHR');
+  } else {
+    return v;
+  }
+}
+
+int get S_IFDIR {
+  final v = get_S_IFDIR();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IFDIR');
+  } else {
+    return v;
+  }
+}
+
+int get S_IFIFO {
+  final v = get_S_IFIFO();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IFIFO');
+  } else {
+    return v;
+  }
+}
+
+int get S_IFLNK {
+  final v = get_S_IFLNK();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IFLNK');
+  } else {
+    return v;
+  }
+}
+
+int get S_IFMT {
+  final v = get_S_IFMT();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IFMT');
+  } else {
+    return v;
+  }
+}
+
+int get S_IFREG {
+  final v = get_S_IFREG();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IFREG');
+  } else {
+    return v;
+  }
+}
+
+int get S_IFSOCK {
+  final v = get_S_IFSOCK();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IFSOCK');
+  } else {
+    return v;
+  }
+}
+
+int get S_IFWHT {
+  final v = get_S_IFWHT();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IFWHT');
+  } else {
+    return v;
+  }
+}
+
+int get S_IREAD {
+  final v = get_S_IREAD();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IREAD');
+  } else {
+    return v;
+  }
+}
+
+int get S_IRGRP {
+  final v = get_S_IRGRP();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IRGRP');
+  } else {
+    return v;
+  }
+}
+
+int get S_IROTH {
+  final v = get_S_IROTH();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IROTH');
+  } else {
+    return v;
+  }
+}
+
+int get S_IRUSR {
+  final v = get_S_IRUSR();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IRUSR');
+  } else {
+    return v;
+  }
+}
+
+int get S_IRWXG {
+  final v = get_S_IRWXG();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IRWXG');
+  } else {
+    return v;
+  }
+}
+
+int get S_IRWXO {
+  final v = get_S_IRWXO();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IRWXO');
+  } else {
+    return v;
+  }
+}
+
+int get S_IRWXU {
+  final v = get_S_IRWXU();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IRWXU');
+  } else {
+    return v;
+  }
+}
+
+int get S_ISGID {
+  final v = get_S_ISGID();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_ISGID');
+  } else {
+    return v;
+  }
+}
+
+int get S_ISTXT {
+  final v = get_S_ISTXT();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_ISTXT');
+  } else {
+    return v;
+  }
+}
+
+int get S_ISUID {
+  final v = get_S_ISUID();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_ISUID');
+  } else {
+    return v;
+  }
+}
+
+int get S_ISVTX {
+  final v = get_S_ISVTX();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_ISVTX');
+  } else {
+    return v;
+  }
+}
+
+int get S_IWGRP {
+  final v = get_S_IWGRP();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IWGRP');
+  } else {
+    return v;
+  }
+}
+
+int get S_IWOTH {
+  final v = get_S_IWOTH();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IWOTH');
+  } else {
+    return v;
+  }
+}
+
+int get S_IWRITE {
+  final v = get_S_IWRITE();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IWRITE');
+  } else {
+    return v;
+  }
+}
+
+int get S_IWUSR {
+  final v = get_S_IWUSR();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IWUSR');
+  } else {
+    return v;
+  }
+}
+
+int get S_IXGRP {
+  final v = get_S_IXGRP();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IXGRP');
+  } else {
+    return v;
+  }
+}
+
+int get S_IXOTH {
+  final v = get_S_IXOTH();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IXOTH');
+  } else {
+    return v;
+  }
+}
+
+int get S_IXUSR {
+  final v = get_S_IXUSR();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('S_IXUSR');
+  } else {
+    return v;
+  }
+}
+
+int get UF_APPEND {
+  final v = get_UF_APPEND();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('UF_APPEND');
+  } else {
+    return v;
+  }
+}
+
+int get UF_HIDDEN {
+  final v = get_UF_HIDDEN();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('UF_HIDDEN');
+  } else {
+    return v;
+  }
+}
+
diff --git a/pkgs/hooks/example/build/native_add_library/lib/src/libc_bindings.dart b/pkgs/hooks/example/build/native_add_library/lib/src/libc_bindings.dart
new file mode 100644
index 0000000000..0ceee9e6a9
--- /dev/null
+++ b/pkgs/hooks/example/build/native_add_library/lib/src/libc_bindings.dart
@@ -0,0 +1,159 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// AUTO GENERATED FILE, DO NOT EDIT.
+//
+// Generated by `package:ffigen`.
+// ignore_for_file: type=lint
+import 'dart:ffi' as ffi;
+
+/// <fcntl.h>
+@ffi.Native<ffi.Int64 Function(ffi.Pointer<ffi.Char>, ffi.Int64, ffi.Int64)>(
+    symbol: 'my_open')
+external int open(
+  ffi.Pointer<ffi.Char> pathname,
+  int flags,
+  int mode,
+);
+
+@ffi.Native<ffi.Int Function(ffi.Pointer<ffi.Char>, ffi.Pointer<ffi.Char>)>(
+    symbol: 'my_rename')
+external int rename(
+  ffi.Pointer<ffi.Char> old,
+  ffi.Pointer<ffi.Char> new$,
+);
+
+/// <unistd.h>
+@ffi.Native<ffi.Int64 Function(ffi.Int64)>(symbol: 'my_close')
+external int close(
+  int fd,
+);
+
+@ffi.Native<ffi.Int64 Function(ffi.Int64, ffi.Pointer<ffi.Char>, ffi.Int64)>()
+external int unlinkat(
+  int dirfd,
+  ffi.Pointer<ffi.Char> pathname,
+  int flags,
+);
+
+/// <errno.h>
+@ffi.Native<ffi.Void Function(ffi.Int64)>(symbol: 'my_seterrno')
+external void seterrno(
+  int err,
+);
+
+@ffi.Native<ffi.Int64 Function()>(symbol: 'my_errno')
+external int errno();
+
+/// <stdlib.h>
+@ffi.Native<ffi.Pointer<ffi.Char> Function(ffi.Pointer<ffi.Char>)>(
+    symbol: 'my_getenv')
+external ffi.Pointer<ffi.Char> getenv(
+  ffi.Pointer<ffi.Char> name,
+);
+
+@ffi.Native<ffi.Pointer<ffi.Char> Function(ffi.Pointer<ffi.Char>)>(
+    symbol: 'my_mkdtemp')
+external ffi.Pointer<ffi.Char> mkdtemp(
+  ffi.Pointer<ffi.Char> template,
+);
+
+@ffi.Native<ffi.Int64 Function(ffi.Pointer<DIR>)>(symbol: 'my_closedir')
+external int closedir(
+  ffi.Pointer<DIR> d,
+);
+
+@ffi.Native<ffi.Pointer<DIR> Function(ffi.Pointer<ffi.Char>)>(
+    symbol: 'my_opendir')
+external ffi.Pointer<DIR> opendir(
+  ffi.Pointer<ffi.Char> path,
+);
+
+@ffi.Native<ffi.Pointer<dirent> Function(ffi.Pointer<DIR>)>(
+    symbol: 'my_readdir')
+external ffi.Pointer<dirent> readdir(
+  ffi.Pointer<DIR> d,
+);
+
+@ffi.Native<ffi.Int64 Function(ffi.Pointer<ffi.Char>, ffi.Int64)>(
+    symbol: 'my_mkdir')
+external int mkdir(
+  ffi.Pointer<ffi.Char> pathname,
+  int mode,
+);
+
+@ffi.Native<ffi.Int64 Function(ffi.Pointer<ffi.Char>, ffi.Pointer<Stat>)>(
+    symbol: 'my_stat')
+external int stat(
+  ffi.Pointer<ffi.Char> path,
+  ffi.Pointer<Stat> buf,
+);
+
+@ffi.Native<ffi.Int64 Function(ffi.Pointer<ffi.Char>, ffi.Pointer<Stat>)>(
+    symbol: 'my_lstat')
+external int lstat(
+  ffi.Pointer<ffi.Char> path,
+  ffi.Pointer<Stat> buf,
+);
+
+@ffi.Native<ffi.Int64 Function(ffi.Int64, ffi.Pointer<Stat>)>(
+    symbol: 'my_fstat')
+external int fstat(
+  int fd,
+  ffi.Pointer<Stat> buf,
+);
+
+/// <dirent.h>
+final class dirent extends ffi.Struct {
+  @ffi.Int64()
+  external int d_ino;
+
+  @ffi.Array.multi([512])
+  external ffi.Array<ffi.Char> d_name;
+}
+
+final class DIR extends ffi.Struct {
+  external dirent my_dirent;
+
+  external ffi.Pointer<ffi.Void> _dir;
+}
+
+/// <sys/stat.h>
+final class timespec extends ffi.Struct {
+  @ffi.Int64()
+  external int tv_sec;
+
+  @ffi.Int64()
+  external int tv_nsec;
+}
+
+final class Stat extends ffi.Struct {
+  @ffi.Int64()
+  external int st_dev;
+
+  @ffi.Int64()
+  external int st_ino;
+
+  @ffi.Int64()
+  external int st_mode;
+
+  @ffi.Int64()
+  external int st_nlink;
+
+  @ffi.Int64()
+  external int std_uid;
+
+  external timespec st_atim;
+
+  external timespec st_mtim;
+
+  external timespec st_ctim;
+
+  /// Only valid on macOS/iOS
+  external timespec st_btime;
+
+  /// Only valid on macOS/iOS
+  @ffi.Int64()
+  external int st_flags;
+}
diff --git a/pkgs/hooks/example/build/native_add_library/pubspec.yaml b/pkgs/hooks/example/build/native_add_library/pubspec.yaml
index 7285f8ea2e..0632ff1bb8 100644
--- a/pkgs/hooks/example/build/native_add_library/pubspec.yaml
+++ b/pkgs/hooks/example/build/native_add_library/pubspec.yaml
@@ -12,6 +12,7 @@ environment:
 
 dependencies:
   code_assets: ^0.19.0
+  ffi: ^2.1.4
   hooks: ^0.19.0
   logging: ^1.3.0
   native_toolchain_c: ^0.16.1-wip
diff --git a/pkgs/hooks/example/build/native_add_library/src/constants.g.c b/pkgs/hooks/example/build/native_add_library/src/constants.g.c
new file mode 100644
index 0000000000..266c19868a
--- /dev/null
+++ b/pkgs/hooks/example/build/native_add_library/src/constants.g.c
@@ -0,0 +1,185 @@
+#include <sys/stat.h>
+
+#include "constants.g.h"
+
+
+int64_t my_get_S_IEXEC(void) {
+#ifdef S_IEXEC
+  return S_IEXEC;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IFBLK(void) {
+#ifdef S_IFBLK
+  return S_IFBLK;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IFCHR(void) {
+#ifdef S_IFCHR
+  return S_IFCHR;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IFDIR(void) {
+#ifdef S_IFDIR
+  return S_IFDIR;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IFIFO(void) {
+#ifdef S_IFIFO
+  return S_IFIFO;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IFLNK(void) {
+#ifdef S_IFLNK
+  return S_IFLNK;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IFMT(void) {
+#ifdef S_IFMT
+  return S_IFMT;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IFREG(void) {
+#ifdef S_IFREG
+  return S_IFREG;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IFSOCK(void) {
+#ifdef S_IFSOCK
+  return S_IFSOCK;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IFWHT(void) {
+#ifdef S_IFWHT
+  return S_IFWHT;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IREAD(void) {
+#ifdef S_IREAD
+  return S_IREAD;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IRGRP(void) {
+#ifdef S_IRGRP
+  return S_IRGRP;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IROTH(void) {
+#ifdef S_IROTH
+  return S_IROTH;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IRUSR(void) {
+#ifdef S_IRUSR
+  return S_IRUSR;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IRWXG(void) {
+#ifdef S_IRWXG
+  return S_IRWXG;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IRWXO(void) {
+#ifdef S_IRWXO
+  return S_IRWXO;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IRWXU(void) {
+#ifdef S_IRWXU
+  return S_IRWXU;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_ISGID(void) {
+#ifdef S_ISGID
+  return S_ISGID;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_ISTXT(void) {
+#ifdef S_ISTXT
+  return S_ISTXT;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_ISUID(void) {
+#ifdef S_ISUID
+  return S_ISUID;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_ISVTX(void) {
+#ifdef S_ISVTX
+  return S_ISVTX;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IWGRP(void) {
+#ifdef S_IWGRP
+  return S_IWGRP;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IWOTH(void) {
+#ifdef S_IWOTH
+  return S_IWOTH;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IWRITE(void) {
+#ifdef S_IWRITE
+  return S_IWRITE;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IWUSR(void) {
+#ifdef S_IWUSR
+  return S_IWUSR;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IXGRP(void) {
+#ifdef S_IXGRP
+  return S_IXGRP;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IXOTH(void) {
+#ifdef S_IXOTH
+  return S_IXOTH;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_S_IXUSR(void) {
+#ifdef S_IXUSR
+  return S_IXUSR;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_UF_APPEND(void) {
+#ifdef UF_APPEND
+  return UF_APPEND;
+#endif
+  return my_UNDEFINED;
+}
+int64_t my_get_UF_HIDDEN(void) {
+#ifdef UF_HIDDEN
+  return UF_HIDDEN;
+#endif
+  return my_UNDEFINED;
+}
diff --git a/pkgs/hooks/example/build/native_add_library/src/constants.g.h b/pkgs/hooks/example/build/native_add_library/src/constants.g.h
new file mode 100644
index 0000000000..7413e9e029
--- /dev/null
+++ b/pkgs/hooks/example/build/native_add_library/src/constants.g.h
@@ -0,0 +1,33 @@
+#include <stdint.h>
+
+#define my_UNDEFINED 9223372036854775807;
+int64_t my_get_S_IEXEC(void);
+int64_t my_get_S_IFBLK(void);
+int64_t my_get_S_IFCHR(void);
+int64_t my_get_S_IFDIR(void);
+int64_t my_get_S_IFIFO(void);
+int64_t my_get_S_IFLNK(void);
+int64_t my_get_S_IFMT(void);
+int64_t my_get_S_IFREG(void);
+int64_t my_get_S_IFSOCK(void);
+int64_t my_get_S_IFWHT(void);
+int64_t my_get_S_IREAD(void);
+int64_t my_get_S_IRGRP(void);
+int64_t my_get_S_IROTH(void);
+int64_t my_get_S_IRUSR(void);
+int64_t my_get_S_IRWXG(void);
+int64_t my_get_S_IRWXO(void);
+int64_t my_get_S_IRWXU(void);
+int64_t my_get_S_ISGID(void);
+int64_t my_get_S_ISTXT(void);
+int64_t my_get_S_ISUID(void);
+int64_t my_get_S_ISVTX(void);
+int64_t my_get_S_IWGRP(void);
+int64_t my_get_S_IWOTH(void);
+int64_t my_get_S_IWRITE(void);
+int64_t my_get_S_IWUSR(void);
+int64_t my_get_S_IXGRP(void);
+int64_t my_get_S_IXOTH(void);
+int64_t my_get_S_IXUSR(void);
+int64_t my_get_UF_APPEND(void);
+int64_t my_get_UF_HIDDEN(void);
diff --git a/pkgs/hooks/example/build/native_add_library/src/native_add_library.c b/pkgs/hooks/example/build/native_add_library/src/native_add_library.c
index cf68dd3ffd..5b9f6187f1 100644
--- a/pkgs/hooks/example/build/native_add_library/src/native_add_library.c
+++ b/pkgs/hooks/example/build/native_add_library/src/native_add_library.c
@@ -4,13 +4,128 @@
 
 #include "native_add_library.h"
 
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
 #ifdef DEBUG
 #include <stdio.h>
 #endif
 
-int32_t add(int32_t a, int32_t b) {
-#ifdef DEBUG
-  printf("Adding %i and %i.\n", a, b);
+int64_t my_open(const char *pathname, int64_t flags, int64_t mode) {
+  return open(pathname, flags, mode);
+}
+
+int my_rename(const char *old, const char *new) { return rename(old, new); }
+
+int64_t my_close(int64_t fd) { return close(fd); }
+
+int64_t my_unlinkat(int64_t dirfd, const char *pathname, int64_t flags) {
+  return unlinkat(dirfd, pathname, flags);
+}
+
+void my_seterrno(int64_t err) { errno = err; }
+
+int64_t my_errno(void) { return errno; }
+
+char *my_getenv(const char *name) { return getenv(name); }
+
+char *my_mkdtemp(char *template) { return mkdtemp(template); }
+
+int64_t my_closedir(my_DIR *d) {
+  int r = closedir(d->_dir);
+  free(d);
+  return r;
+}
+
+my_DIR *my_opendir(const char *path) {
+  my_DIR *myd = malloc(sizeof(my_DIR));
+
+  DIR *d = opendir(path);
+  if (d == NULL) {
+    return NULL;
+  }
+  myd->_dir = d;
+  return myd;
+}
+
+struct my_dirent *my_readdir(my_DIR *myd) {
+  struct dirent *d = readdir(myd->_dir);
+  if (d == NULL) {
+    return NULL;
+  }
+
+  myd->my_dirent.d_ino = d->d_ino;
+  strncpy(myd->my_dirent.d_name, d->d_name, sizeof(myd->my_dirent.d_name));
+  return &(myd->my_dirent);
+}
+
+static void _fill(struct my_Stat *buf, struct stat *s) {
+  buf->st_dev = s->st_dev;
+  buf->st_ino = s->st_ino;
+  buf->st_mode = s->st_mode;
+  buf->st_nlink = s->st_nlink;
+  buf->std_uid = s->st_uid;
+#ifdef __APPLE__
+  buf->st_atim.tv_sec = s->st_atimespec.tv_sec;
+  buf->st_atim.tv_nsec = s->st_atimespec.tv_nsec;
+
+  buf->st_ctim.tv_sec = s->st_ctimespec.tv_sec;
+  buf->st_ctim.tv_nsec = s->st_ctimespec.tv_nsec;
+
+  buf->st_mtim.tv_sec = s->st_mtimespec.tv_sec;
+  buf->st_mtim.tv_nsec = s->st_mtimespec.tv_nsec;
+
+  buf->st_btime.tv_sec = s->st_birthtimespec.tv_sec;
+  buf->st_btime.tv_nsec = s->st_birthtimespec.tv_nsec;
+
+  buf->st_flags = s->st_flags;
+#elif
+  // https://man7.org/linux/man-pages/man3/stat.3type.html
+
+  buf->st_atim.tv_sec = s->st_atim.tv_sec;
+  buf->st_atim.tv_nsec = s->st_atim.tv_nsec;
+
+  buf->st_ctim.tv_sec = s->st_ctim.tv_sec;
+  buf->st_ctim.tv_nsec = s->st_ctim.tv_nsec;
+
+  buf->st_mtim.tv_sec = s->st_mtim.tv_sec;
+  buf->st_mtim.tv_nsec = s->st_mtim.tv_nsec;
 #endif
-  return a + b;
+}
+
+int64_t my_mkdir(const char *pathname, int64_t mode) {
+  return mkdir(pathname, mode);
+}
+
+int64_t my_stat(const char *path, struct my_Stat *buf) {
+  struct stat s;
+  int r = stat(path, &s);
+  if (r != -1) {
+    _fill(buf, &s);
+  }
+  return r;
+}
+
+int64_t my_lstat(const char *path, struct my_Stat *buf) {
+  struct stat s;
+  int r = lstat(path, &s);
+  if (r != -1) {
+    _fill(buf, &s);
+  }
+  return r;
+}
+
+int64_t my_fstat(int64_t fd, struct my_Stat *buf) {
+  struct stat s;
+  int r = fstat(fd, &s);
+  if (r != -1) {
+    _fill(buf, &s);
+  }
+  return r;
 }
diff --git a/pkgs/hooks/example/build/native_add_library/src/native_add_library.h b/pkgs/hooks/example/build/native_add_library/src/native_add_library.h
index 5824f98a7d..dd34ce857d 100644
--- a/pkgs/hooks/example/build/native_add_library/src/native_add_library.h
+++ b/pkgs/hooks/example/build/native_add_library/src/native_add_library.h
@@ -10,4 +10,66 @@
 #define MYLIB_EXPORT
 #endif
 
-MYLIB_EXPORT int32_t add(int32_t a, int32_t b);
+// <fcntl.h>
+MYLIB_EXPORT int64_t my_open(const char *pathname, int64_t flags, int64_t mode);
+
+// <stdio.h>
+MYLIB_EXPORT int my_rename(const char *old, const char *new);
+
+// <unistd.h>
+
+MYLIB_EXPORT int64_t my_close(int64_t fd);
+MYLIB_EXPORT int64_t my_unlinkat(int64_t dirfd, const char *pathname,
+                              int64_t flags);
+
+// <errno.h>
+MYLIB_EXPORT void my_seterrno(int64_t err);
+MYLIB_EXPORT int64_t my_errno(void);
+
+// <stdlib.h>
+MYLIB_EXPORT char *my_getenv(const char *name);
+MYLIB_EXPORT char *my_mkdtemp(char *template);
+
+// <dirent.h>
+
+struct my_dirent {
+  int64_t d_ino;
+  char d_name[512];
+};
+
+typedef struct {
+  struct my_dirent my_dirent;
+  void *_dir;
+} my_DIR;
+
+MYLIB_EXPORT int64_t my_closedir(my_DIR *d);
+MYLIB_EXPORT my_DIR *my_opendir(const char *path);
+MYLIB_EXPORT struct my_dirent *my_readdir(my_DIR *d);
+
+// <sys/stat.h>
+struct my_timespec {
+  int64_t tv_sec;
+  int64_t tv_nsec;
+};
+
+struct my_Stat {
+  int64_t st_dev;
+  int64_t st_ino;
+  int64_t st_mode;
+  int64_t st_nlink;
+  int64_t std_uid;
+
+  struct my_timespec st_atim;
+  struct my_timespec st_mtim;
+  struct my_timespec st_ctim;
+  // Only valid on macOS/iOS
+  struct my_timespec st_btime;
+
+  // Only valid on macOS/iOS
+  int64_t st_flags;
+};
+
+MYLIB_EXPORT int64_t my_mkdir(const char *pathname, int64_t mode);
+MYLIB_EXPORT int64_t my_stat(const char *path, struct my_Stat *buf);
+MYLIB_EXPORT int64_t my_lstat(const char *path, struct my_Stat *buf);
+MYLIB_EXPORT int64_t my_fstat(int64_t fd, struct my_Stat *buf);
diff --git a/pkgs/hooks/example/build/native_add_library/test/native_add_library_test.dart b/pkgs/hooks/example/build/native_add_library/test/native_add_library_test.dart
index 692446e2e5..c7bb825931 100644
--- a/pkgs/hooks/example/build/native_add_library/test/native_add_library_test.dart
+++ b/pkgs/hooks/example/build/native_add_library/test/native_add_library_test.dart
@@ -2,11 +2,60 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:ffi';
+
+import 'package:ffi/ffi.dart';
 import 'package:native_add_library/native_add_library.dart';
 import 'package:test/test.dart';
 
+// Symbols currently in use by io_file:
+// errno
+// close
+// open
+// getenv
+// fstat
+// rename
+// unlinkat
+// mkdtemp
+// mkdir
+// stat
+// strerror
+// error constants
+// + 5 or 6 constants
 void main() {
-  test('invoke native function', () {
-    expect(add(24, 18), 42);
-  });
+  test(
+    'invoke native function',
+    () => using((arena) {
+      final fd = open('foobarbaz'.toNativeUtf8(allocator: arena).cast(), 0, 0);
+      print('fd: $fd');
+      print('errno: $errno');
+
+      final s = arena<Stat>();
+      final r = stat('/'.toNativeUtf8(allocator: arena).cast(), s);
+      print(r);
+      print(s.ref.st_dev);
+      print(s.ref.st_ino);
+      print(s.ref.st_mode);
+      print(s.ref.st_btime.tv_sec);
+
+      print('UF_HIDDEN: $UF_HIDDEN');
+      print('S_IFMT: $S_IFMT');
+
+      final d = opendir('/'.toNativeUtf8(allocator: arena).cast());
+      if (d == nullptr) {
+        print('open failed');
+      }
+      final h = readdir(d);
+      final b = StringBuffer();
+      for (var i = 0; ; i++) {
+        if (h.ref.d_name[i] == 0) {
+          print(b);
+          break;
+        } else {
+          b.writeCharCode(h.ref.d_name[i]);
+        }
+      }
+      closedir(d);
+    }),
+  );
 }
diff --git a/pkgs/hooks/example/build/native_add_library/tool/build_constants.dart b/pkgs/hooks/example/build/native_add_library/tool/build_constants.dart
new file mode 100644
index 0000000000..021e1da03b
--- /dev/null
+++ b/pkgs/hooks/example/build/native_add_library/tool/build_constants.dart
@@ -0,0 +1,71 @@
+import 'dart:convert';
+import 'dart:io';
+
+const _cSourceTemplate = '''
+#include <sys/stat.h>
+
+#include "constants.g.h"
+
+
+''';
+
+const _cHeaderTemplate = '''
+#include <stdint.h>
+
+#define my_UNDEFINED 9223372036854775807;
+''';
+
+const _dartTemplate = '''
+// ignore_for_file: non_constant_identifier_names
+
+import 'constant_bindings.dart';
+''';
+
+void addConstantToCSource(String constant, StringBuffer b) {
+  b.write('''
+int64_t my_get_$constant(void) {
+#ifdef $constant
+  return $constant;
+#endif
+  return my_UNDEFINED;
+}
+''');
+}
+
+void addConstantToCHeader(String constant, StringBuffer b) {
+  b.write('''
+int64_t my_get_$constant(void);
+''');
+}
+
+void addConstantToDart(String constant, StringBuffer b) {
+  b.writeln('''
+int get $constant {
+  final v = get_$constant();
+  if (v == my_UNDEFINED) {
+    throw UnsupportedError('$constant');
+  } else {
+    return v;
+  }
+}
+''');
+}
+
+void main() {
+  final constants =
+      (json.decode(File('constants.json').readAsStringSync()) as List)
+          .cast<String>();
+
+  final cSourceBuffer = StringBuffer(_cSourceTemplate);
+  final cHeaderBuffer = StringBuffer(_cHeaderTemplate);
+  final dartBuffer = StringBuffer(_dartTemplate);
+
+  for (final constant in constants) {
+    addConstantToCHeader(constant, cHeaderBuffer);
+    addConstantToCSource(constant, cSourceBuffer);
+    addConstantToDart(constant, dartBuffer);
+  }
+  File('lib/src/constants.g.dart').writeAsStringSync(dartBuffer.toString());
+  File('src/constants.g.c').writeAsStringSync(cSourceBuffer.toString());
+  File('src/constants.g.h').writeAsStringSync(cHeaderBuffer.toString());
+}