Add macOS support and CI workflow

.github/workflows/run_examples.yml

@@ -0,0 +1,30 @@
+name: Run examples
+
+on: [push, pull_request]
+
+env:
+  CGO_ENABLED: 0
+
+jobs:
+  run:
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.22.x'
+      - name: Install libffi
+        if: runner.os == 'macOS'
+        run: |
+          brew update
+          brew install libffi
+      - name: Run example
+        run: go run examples/simple/cos/main_unix.go
+        env:
+          DYLD_FALLBACK_LIBRARY_PATH: $DYLD_FALLBACK_LIBRARY_PATH:/opt/homebrew/opt/libffi/lib

README.md

@@ -8,6 +8,8 @@ You can use [purego](https://github.com/ebitengine/purego) to call C code withou
 
 ## Requirements
 ### OS/Architecture
+- darwin/amd64
+- darwin/arm64
 - freebsd/amd64
 - freebsd/arm64
 - linux/amd64
@@ -42,6 +44,16 @@ Note: Use this `-gcflags="github.com/ebitengine/purego/internal/fakecgo=-std"` b
 #### Windows
 You need a `libffi-8.dll` next to the executable/root folder of your project or inside C:\Windows\System32. If you don't want to build libffi from source, you can find this dll for example inside the [Windows embeddable package](https://www.python.org/downloads/windows/) of Python.
 
+#### macOS
+You can use [Homebrew](https://brew.sh/) to install libffi:
+```sh
+brew install libffi
+```
+Note: If dlopen can't find the libffi.8.dylib file, you can try setting this environment variable:
+```sh
+export DYLD_FALLBACK_LIBRARY_PATH=$DYLD_FALLBACK_LIBRARY_PATH:/opt/homebrew/opt/libffi/lib
+```
+
 ## Examples
 In this example we use the puts function inside the standard C library to print "Hello World!" to the console:
 

abi.go

@@ -1,4 +1,4 @@
-//go:build ((freebsd || linux) && arm64) || (windows && (amd64 || arm64))
+//go:build ((freebsd || linux || darwin) && arm64) || (windows && (amd64 || arm64))
 
 package ffi
 

abi_amd64.go

@@ -1,4 +1,4 @@
-//go:build freebsd || linux
+//go:build freebsd || linux || darwin
 
 package ffi
 

examples/simple/cos/main_unix.go

@@ -1,4 +1,4 @@
-//go:build (freebsd || linux) && (amd64 || arm64)
+//go:build (freebsd || linux || darwin) && (amd64 || arm64)
 
 package main
 
@@ -18,6 +18,8 @@ func main() {
 		filename = "libm.so.6"
 	case "freebsd":
 		filename = "libm.so.5"
+	case "darwin":
+		filename = "libm.dylib"
 	}
 
 	// open the shared library

ffi.go

@@ -1,4 +1,4 @@
-//go:build (freebsd || linux || windows) && (amd64 || arm64)
+//go:build (freebsd || linux || windows || darwin) && (amd64 || arm64)
 
 package ffi
 

ffi_darwin.go

@@ -0,0 +1,31 @@
+//go:build darwin && (amd64 || arm64)
+
+package ffi
+
+import (
+	"github.com/ebitengine/purego"
+)
+
+func init() {
+	const filename = "libffi.8.dylib"
+
+	libffi, err := purego.Dlopen(filename, purego.RTLD_LAZY)
+	if err != nil {
+		panic(err)
+	}
+
+	prepCif, err = purego.Dlsym(libffi, "ffi_prep_cif")
+	if err != nil {
+		panic(err)
+	}
+
+	prepCifVar, err = purego.Dlsym(libffi, "ffi_prep_cif_var")
+	if err != nil {
+		panic(err)
+	}
+
+	call, err = purego.Dlsym(libffi, "ffi_call")
+	if err != nil {
+		panic(err)
+	}
+}

types.go

@@ -1,4 +1,4 @@
-//go:build (freebsd || linux || windows) && (amd64 || arm64)
+//go:build (freebsd || linux || windows || darwin) && (amd64 || arm64)
 
 package ffi