diff --git a/src/header/grp/mod.rs b/src/header/grp/mod.rs
index e4bb1e0b8b..ec013240c5 100644
--- a/src/header/grp/mod.rs
+++ b/src/header/grp/mod.rs
@@ -515,7 +515,7 @@ pub unsafe extern "C" fn getgrouplist(
     if groups_found as usize > grps.len() {
         -1
     } else {
-        grps.len() as c_int
+        groups_found
     }
 }