diff --git a/libs/binder/OS.h b/libs/binder/OS.h
index 0d38968..fecae31 100644
--- a/libs/binder/OS.h
+++ b/libs/binder/OS.h
@@ -33,11 +33,11 @@
 
 std::unique_ptr<RpcTransportCtxFactory> makeDefaultRpcTransportCtxFactory();
 
-int sendMessageOnSocket(
+ssize_t sendMessageOnSocket(
         const RpcTransportFd& socket, iovec* iovs, int niovs,
         const std::vector<std::variant<base::unique_fd, base::borrowed_fd>>* ancillaryFds);
 
-int receiveMessageFromSocket(
+ssize_t receiveMessageFromSocket(
         const RpcTransportFd& socket, iovec* iovs, int niovs,
         std::vector<std::variant<base::unique_fd, base::borrowed_fd>>* ancillaryFds);