diff --git a/libs/binder/OS.cpp b/libs/binder/OS.cpp
index 77e401f..ce60e33 100644
--- a/libs/binder/OS.cpp
+++ b/libs/binder/OS.cpp
@@ -67,7 +67,7 @@
     return RpcTransportCtxFactoryRaw::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) {
     if (ancillaryFds != nullptr && !ancillaryFds->empty()) {
@@ -112,7 +112,7 @@
     return TEMP_FAILURE_RETRY(sendmsg(socket.fd.get(), &msg, MSG_NOSIGNAL));
 }
 
-int receiveMessageFromSocket(
+ssize_t receiveMessageFromSocket(
         const RpcTransportFd& socket, iovec* iovs, int niovs,
         std::vector<std::variant<base::unique_fd, base::borrowed_fd>>* ancillaryFds) {
     if (ancillaryFds != nullptr) {
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);
 
diff --git a/libs/binder/RpcTransportRaw.cpp b/libs/binder/RpcTransportRaw.cpp
index 1912d14..cd067bf 100644
--- a/libs/binder/RpcTransportRaw.cpp
+++ b/libs/binder/RpcTransportRaw.cpp
@@ -61,7 +61,8 @@
             override {
         bool sentFds = false;
         auto send = [&](iovec* iovs, int niovs) -> ssize_t {
-            int ret = sendMessageOnSocket(mSocket, iovs, niovs, sentFds ? nullptr : ancillaryFds);
+            ssize_t ret =
+                    sendMessageOnSocket(mSocket, iovs, niovs, sentFds ? nullptr : ancillaryFds);
             sentFds |= ret > 0;
             return ret;
         };
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;