diff --git a/libs/binder/trusty/OS.cpp b/libs/binder/trusty/OS.cpp
index 397ff41..8ec9823 100644
--- a/libs/binder/trusty/OS.cpp
+++ b/libs/binder/trusty/OS.cpp
@@ -59,14 +59,14 @@
     return RpcTransportCtxFactoryTipcTrusty::make();
 }
 
-int sendMessageOnSocket(
+ssize_t sendMessageOnSocket(
         const RpcTransportFd& /* socket */, iovec* /* iovs */, int /* niovs */,
         const std::vector<std::variant<base::unique_fd, base::borrowed_fd>>* /* ancillaryFds */) {
     errno = ENOTSUP;
     return -1;
 }
 
-int receiveMessageFromSocket(
+ssize_t receiveMessageFromSocket(
         const RpcTransportFd& /* socket */, iovec* /* iovs */, int /* niovs */,
         std::vector<std::variant<base::unique_fd, base::borrowed_fd>>* /* ancillaryFds */) {
     errno = ENOTSUP;