README

Learning-focused sample of a PHP extension that calls Zig through a C ABI (FFI boundary).

Learning goals

• Understand how PHP extension C code calls a Zig function.
• Understand how Zig builds a static library consumed by PHP extension build.
• Understand how PIE metadata points to the extension build directory.

Project layout

• composer.json: PIE metadata (type: php-ext, build path, extension name)
• ext/config.m4: phpize/autoconf build integration and Zig library linking
• ext/hello_zig.c: PHP function registration and call into Zig ABI
• ext/zig/build.zig: Zig static library build definition
• ext/zig/src/hellozig.zig: exported Zig function (hellozig_message)
• ext/zig/src/hellozig.h: C header consumed from hello_zig.c
• ext/tests/001_hello_zig_hello.phpt: runtime behavior test

How the call flow works

1. PHP userland calls hello_zig_hello().
2. PHP extension C code (ext/hello_zig.c) invokes hellozig_message().
3. hellozig_message() is implemented in Zig and exported with C ABI.
4. Returned C string is sent back to PHP as a string result.

Install with PIE (from Packagist)

This package is intended to be installable from Packagist:

• https://packagist.org/packages/masakielastic/hello-zig

Example:

pie install masakielastic/hello-zig
php --ri hello_zig
php -r 'echo hello_zig_hello(), PHP_EOL;'

Expected output:

Hello World from Zig FFI!

Build and run (from clean state)

Prerequisites:

• phpize and PHP development headers
• Zig compiler (on PATH, or provided via ZIG=/path/to/zig)

cd ext
phpize
ZIG=/home/masakielastic/.local/zig-dev/zig ./configure --enable-hello-zig
make
php -dextension=modules/hello_zig.so -r 'echo hello_zig_hello(), PHP_EOL;'

Expected output:

Hello World from Zig FFI!

Run tests

cd ext
make test TESTS=tests/001_hello_zig_hello.phpt

What to edit while learning

• Change return text: ext/zig/src/hellozig.zig
• Add new PHP function: ext/hello_zig.c (function entry table + implementation)
• Add new Zig export and header declaration: ext/zig/src/hellozig.zig and ext/zig/src/hellozig.h
• Add regression test: ext/tests/*.phpt

Troubleshooting

• zig command not found:
  • Pass explicit path: ZIG=/absolute/path/to/zig ./configure --enable-hello-zig
• Build errors after file moves:
  • Re-run from clean build dir: phpize then ./configure then make
• Extension not loading:
  • Confirm .so exists at ext/modules/hello_zig.so
  • Use absolute path in -dextension=...