Call Rust function from C: Skeleton

[learn-rust.git] / call-rust-from-c / src / lib.rs

diff --git a/call-rust-from-c/src/lib.rs b/call-rust-from-c/src/lib.rs
new file mode 100644 (file)
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+++ b/call-rust-from-c/src/lib.rs
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+use std::os::raw;
+
+/// Return The Answer.
+///
+/// # Example
+///
+/// ```
+/// let a = call_rust_from_c::answer();
+/// assert_eq!(a, 42);
+/// ```
+#[no_mangle]
+// C 'int'; it does not actually hurt to have more specific types such as int32_t, but it's good to know that plain ints work
+pub extern "C" fn answer() -> raw::c_int {
+    return 42;
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_answer() {
+        assert_eq!(answer(), 42);
+    }
+}