diff --git a/build.rs b/build.rs
index 7449918..66e16ac 100644
--- a/build.rs
+++ b/build.rs
@@ -14,6 +14,7 @@ fn run_cbindgen(cargo_dir: &Path, target_dir: &Path) {
     cbindgen::Builder::new()
         .with_crate(cargo_dir)
         .with_language(cbindgen::Language::Cxx)
+        .with_pragma_once(true)
         .generate()
         .expect("Unable to generate bindings")
         .write_to_file(&out);