Add an example for using a build script

examples/build-script/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "build-script"
+version = "0.1.0"
+authors = ["Ryan Hunt <rhunt@eqrion.net>"]
+build = "build.rs"
+
+[build-dependencies]
+cbindgen = { path = "../../" }

examples/build-script/build.rs

@@ -0,0 +1,11 @@
+extern crate cbindgen;
+
+use cbindgen::{Config, Library};
+
+fn main() {
+    let config = Config::default();
+
+    Library::load("../build-script", &config)
+        .build(&config).unwrap()
+        .write_to_file(&config, "bindings.h");
+}

examples/build-script/src/lib.rs

@@ -0,0 +1,19 @@
+#![allow(dead_code)]
+#![allow(unused_variables)]
+
+pub struct Opaque {
+    x: i32,
+    y: f32,
+}
+
+#[repr(C)]
+pub struct Normal {
+    x: i32,
+    y: f32,
+}
+
+#[no_mangle]
+pub extern "C" fn root(x: *mut Opaque, y: Normal)
+{
+
+}

src/bindgen/library.rs

@@ -1,6 +1,7 @@
 use std::io::Write;
 use std::collections::BTreeMap;
 use std::cmp::Ordering;
+use std::fs::File;
 
 use syn::*;
 
@@ -327,6 +328,11 @@ impl BuiltLibrary {
         }
     }
 
+    pub fn write_to_file(&self, config: &Config, path: &str) {
+        self.write(&config,
+                   &mut File::create(path).unwrap());
+    }
+
     pub fn write<F: Write>(&self, config: &Config, out: &mut F) {
         if let Some(ref f) = config.file_header {
             write!(out, "{}\n", f).unwrap();