diff --git a/src/c_api/c_api.cc b/src/c_api/c_api.cc
index 614e0acc63cf..192da4961b25 100644
--- a/src/c_api/c_api.cc
+++ b/src/c_api/c_api.cc
@@ -948,8 +948,8 @@ XGB_DLL int XGBoosterLoadModelFromBuffer(BoosterHandle handle,
 }
 
 XGB_DLL int XGBoosterGetModelRaw(BoosterHandle handle,
-                         xgboost::bst_ulong* out_len,
-                         const char** out_dptr) {
+                                 xgboost::bst_ulong* out_len,
+                                 const char** out_dptr) {
   std::string& raw_str = XGBAPIThreadLocalStore::Get()->ret_str;
   raw_str.resize(0);