diff --git a/src/agent.c b/src/agent.c
index ce4ce16e..3a15183e 100644
--- a/src/agent.c
+++ b/src/agent.c
@@ -425,11 +425,14 @@ cleanup:
     int rc;                                                            \
                                                                        \
     while(*(total) < (length)) {                                       \
-        if(!(agent)->pending_io)                                       \
+        if(!(agent)->pending_io) {                                     \
             ret = (func)((agent)->pipe, (char *)(buffer) + *(total),   \
                          (DWORD)((length) - *(total)),                 \
                          &bytes_transferred,                           \
                          &(agent)->overlapped);                        \
+            if(ret && !bytes_transferred)                              \
+                return LIBSSH2_ERROR_SOCKET_DISCONNECT;                \
+        }                                                              \
         else                                                           \
             ret = GetOverlappedResult((agent)->pipe,                   \
                                       &(agent)->overlapped,            \
@@ -619,6 +622,8 @@ static int agent_connect_unix(LIBSSH2_AGENT *agent)
                         flags, abstract);                                 \
             if(rc < 0)                                                    \
                 return rc;                                                \
+            else if(!rc)                                                  \
+                return LIBSSH2_ERROR_SOCKET_DISCONNECT;                   \
                                                                           \
             finished += rc;                                               \
         }                                                                 \