From 930924cdf581f403cc62aa61d91c759faa60f6f6 Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Sun, 19 Apr 2015 10:28:20 -0700
Subject: [PATCH] Add C to Rust example

---
 c-to-rust/Cargo.toml |  8 ++++++++
 c-to-rust/Makefile   | 18 ++++++++++++++++++
 c-to-rust/src/lib.rs |  6 ++++++
 c-to-rust/src/main.c | 11 +++++++++++
 4 files changed, 43 insertions(+)
 create mode 100644 c-to-rust/Cargo.toml
 create mode 100644 c-to-rust/Makefile
 create mode 100644 c-to-rust/src/lib.rs
 create mode 100644 c-to-rust/src/main.c

diff --git a/c-to-rust/Cargo.toml b/c-to-rust/Cargo.toml
new file mode 100644
index 0000000..e00dfb6
--- /dev/null
+++ b/c-to-rust/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "c-to-rust"
+version = "0.1.0"
+authors = ["Alex Crichton <alex@alexcrichton.com>"]
+
+[lib]
+name = "double_input"
+crate-type = ["staticlib"]
diff --git a/c-to-rust/Makefile b/c-to-rust/Makefile
new file mode 100644
index 0000000..d39910e
--- /dev/null
+++ b/c-to-rust/Makefile
@@ -0,0 +1,18 @@
+all: target/double
+	target/double
+
+target:
+	mkdir -p $@
+
+target/double: target/main.o target/libdouble_input.a
+	$(CC) -o $@ -Wl,--gc-sections $^ -lpthread
+
+target/libdouble_input.a: src/lib.rs Cargo.toml
+	cargo build
+	(cd target && ln -nsf debug/libdouble_input-*.a libdouble_input.a)
+
+target/main.o: src/main.c | target
+	$(CC) -o $@ -c $<
+
+clean:
+	rm -rf target
diff --git a/c-to-rust/src/lib.rs b/c-to-rust/src/lib.rs
new file mode 100644
index 0000000..ae41d1f
--- /dev/null
+++ b/c-to-rust/src/lib.rs
@@ -0,0 +1,6 @@
+#![crate_type = "staticlib"]
+
+#[no_mangle]
+pub extern fn double_input(input: i32) -> i32 {
+    input * 2
+}
diff --git a/c-to-rust/src/main.c b/c-to-rust/src/main.c
new file mode 100644
index 0000000..ae7bef3
--- /dev/null
+++ b/c-to-rust/src/main.c
@@ -0,0 +1,11 @@
+#include <stdint.h>
+#include <stdio.h>
+
+extern int32_t double_input(int32_t input);
+
+int main() {
+    int input = 4;
+    int output = double_input(input);
+    printf("%d * 2 = %d\n", input, output);
+    return 0;
+}