fortran example

rust-to-fortran/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "rust-to-fortran"
+version = "0.1.0"
+build = "build.rs"
+
+[dependencies]
+libc = "0.2"
+
+[build-dependencies]
+cc = "1.0"

rust-to-fortran/build.rs

@@ -0,0 +1,7 @@
+extern crate cc;
+
+fn main() {
+    cc::Build::new()
+        .file("src/double.f90")
+        .compile("libdouble.a");
+}

rust-to-fortran/src/double.f90

@@ -0,0 +1,16 @@
+module wrapper
+
+    implicit none
+    private
+    public double_input
+
+contains
+
+    function double_input(input)
+        implicit none
+        integer :: input, double_input
+
+        double_input = 2*input
+    end function
+
+end module wrapper

rust-to-fortran/src/main.rs

@@ -0,0 +1,13 @@
+extern crate libc;
+
+// Consider using the `nm` utility on compiled Fortran files to get the function names
+
+extern {
+    fn __wrapper_MOD_double_input(input: &libc::c_int) -> libc::c_int;
+}
+
+fn main() {
+    let input = 4;
+    let output = unsafe { __wrapper_MOD_double_input(&input) };
+    println!("{} * 2 = {}", input, output);
+}