diff --git a/apex/contrib/csrc/transducer/transducer_joint_kernel.cu b/apex/contrib/csrc/transducer/transducer_joint_kernel.cu
index 05c64320b..7c1c7c291 100755
--- a/apex/contrib/csrc/transducer/transducer_joint_kernel.cu
+++ b/apex/contrib/csrc/transducer/transducer_joint_kernel.cu
@@ -1,3 +1,4 @@
+#include <cstring>
 #include <cuda.h>
 #include <curand_kernel.h>
 #include <cuda_runtime.h>