From fe876a4442b3faf2647c6696731f6c176c211d55 Mon Sep 17 00:00:00 2001
From: MarkRivers <rivers@cars.uchicago.edu>
Date: Thu, 24 Jun 2004 19:52:09 +0000
Subject: [PATCH] Fixed bug with NULL pointer on non-vxWorks systems

---
 motorApp/AcsSrc/devMCB4B.cc | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/motorApp/AcsSrc/devMCB4B.cc b/motorApp/AcsSrc/devMCB4B.cc
index b699c493..8bf295af 100644
--- a/motorApp/AcsSrc/devMCB4B.cc
+++ b/motorApp/AcsSrc/devMCB4B.cc
@@ -166,8 +166,9 @@ STATIC RTN_STATUS MCB4B_build_trans(motor_cmnd command, double *parms, struct mo
     send = true;
     rtnval = OK;
     buff[0] = '\0';
-    dval = parms[0];
-    ival = NINT(parms[0]);
+    /* Protect against NULL pointer with WRTITE_MSG(GO/STOP_AXIS/GET_INFO, NULL). */
+    dval = (parms == NULL) ? 0.0 : *parms;
+    ival = NINT(dval);
 
     rtnval = (RTN_STATUS) motor_start_trans_com(mr, MCB4B_cards);
     Debug(5, "MCB4B_build_trans: entry, motor_start_trans_com=%d\n", rtnval);