diff --git a/onnxruntime/core/session/custom_ops.cc b/onnxruntime/core/session/custom_ops.cc
index 165bb13ecd..a821a718de 100644
--- a/onnxruntime/core/session/custom_ops.cc
+++ b/onnxruntime/core/session/custom_ops.cc
@@ -29,11 +29,11 @@ ORT_API_STATUS_IMPL(OrtKernelInfoGetAttribute_int64, _In_ const OrtKernelInfo* i
   return onnxruntime::ToOrtStatus(status);
 }
 
-OrtValue* OrtKernelContext_GetInput(OrtKernelContext* context, _In_ size_t index) {
+ORT_API(OrtValue*, OrtKernelContext_GetInput, OrtKernelContext* context, _In_ size_t index) {
   return reinterpret_cast<OrtValue*>(const_cast<onnxruntime::MLValue*>(reinterpret_cast<onnxruntime::OpKernelContextInternal*>(context)->GetInputMLValue(index)));
 };
 
-OrtValue* OrtKernelContext_GetOutput(OrtKernelContext* context, _In_ size_t index, _In_ const int64_t* dim_values, size_t dim_count) {
+ORT_API(OrtValue*, OrtKernelContext_GetOutput, OrtKernelContext* context, _In_ size_t index, _In_ const int64_t* dim_values, size_t dim_count) {
   onnxruntime::TensorShape shape(dim_values, dim_count);
   return reinterpret_cast<OrtValue*>(reinterpret_cast<onnxruntime::OpKernelContextInternal*>(context)->OutputMLValue(index, shape));
 };