diff --git a/src/installer.rs b/src/installer.rs
index 6336947..908d75a 100644
--- a/src/installer.rs
+++ b/src/installer.rs
@@ -37,7 +37,7 @@ struct Unshield {
     _private: [u8; 0],
 }
 
-extern "C" {
+unsafe extern "C" {
     fn unshield_open(filename: *const c_char) -> *mut Unshield;
     fn unshield_close(unshield: *mut Unshield);