From c69536fc8e2a26ccd28f8ca20ed87eafbbb136b3 Mon Sep 17 00:00:00 2001
From: Jeff Hill <johill@lanl.gov>
Date: Tue, 28 Oct 2003 16:05:49 +0000
Subject: [PATCH] return an error condition if they try to start a preemptive
 callback enabled context when the thread already has a single threaded
 context.

---
 src/ca/access.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/ca/access.cpp b/src/ca/access.cpp
index 7e263517e..0f1816210 100644
--- a/src/ca/access.cpp
+++ b/src/ca/access.cpp
@@ -194,6 +194,10 @@ int epicsShareAPI ca_context_create (
 
         pcac = ( ca_client_context * ) epicsThreadPrivateGet ( caClientContextId );
 	    if ( pcac ) {
+            if ( premptiveCallbackSelect == ca_enable_preemptive_callback &&
+                ! pcac->preemptiveCallbakIsEnabled() ) {
+                return ECA_NOTTHREADED;
+            }
 		    return ECA_NORMAL;
 	    }