From 8c1e83ee8e86819e77b7cc9042b914cd12e5443f Mon Sep 17 00:00:00 2001
From: Andreas Karlsson <andreas.karlsson@rt-labs.com>
Date: Fri, 24 May 2019 14:27:41 +0200
Subject: [PATCH] Add extra ERROR on mailbox receive timeout to improv
 diagnostics possibilities

---
 soem/ethercatmain.c | 3 ++-
 soem/ethercattype.h | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/soem/ethercatmain.c b/soem/ethercatmain.c
index e91c7e8..795a21c 100644
--- a/soem/ethercatmain.c
+++ b/soem/ethercatmain.c
@@ -1097,7 +1097,8 @@ int ecx_mbxreceive(ecx_contextt *context, uint16 slave, ec_mbxbuft *mbx, int tim
       }
       else /* no read mailbox available */
       {
-          wkc = 0;
+         if (wkc > 0)
+            wkc = EC_TIMEOUT;
       }
    }
 
diff --git a/soem/ethercattype.h b/soem/ethercattype.h
index 9dc2f84..6b4d17c 100644
--- a/soem/ethercattype.h
+++ b/soem/ethercattype.h
@@ -45,6 +45,8 @@ extern "C"
 #define EC_ERROR              -3
 /** return value too many slaves */
 #define EC_SLAVECOUNTEXCEEDED -4
+/** return value request timeout */
+#define EC_TIMEOUT            -5
 /** maximum EtherCAT frame length in bytes */
 #define EC_MAXECATFRAME    1518
 /** maximum EtherCAT LRW frame length in bytes */