From 3cae287deadf72c8d07640d1d6a765cbc9ecff88 Mon Sep 17 00:00:00 2001
From: Jiaming Yuan <jm.yuan@outlook.com>
Date: Tue, 14 Jul 2020 18:34:19 +0800
Subject: [PATCH] Fix NDK Build. (#5886)

* Explicit cast for slice.
---
 src/c_api/c_api.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/c_api/c_api.cc b/src/c_api/c_api.cc
index c3d814d445eb..aa6ecf43a784 100644
--- a/src/c_api/c_api.cc
+++ b/src/c_api/c_api.cc
@@ -227,7 +227,8 @@ XGB_DLL int XGDMatrixSliceDMatrixEx(DMatrixHandle handle,
         << "slice does not support group structure";
   }
   DMatrix* dmat = static_cast<std::shared_ptr<DMatrix>*>(handle)->get();
-  *out = new std::shared_ptr<DMatrix>(dmat->Slice({idxset, len}));
+  *out = new std::shared_ptr<DMatrix>(
+      dmat->Slice({idxset, static_cast<std::size_t>(len)}));
   API_END();
 }