WIP state for Hugo to potentially fix a segfault

bus/m_epics_ca.tpp

@@ -122,21 +122,6 @@ mEpicsCa<T>::mEpicsCa(const char *pChanName, bool subscribe,
     dbfFromType<T>();
     int status = CM_SUCCESS;
 
-    /*
-    ca_disable_preemptive_callback: No callback thread is created and CA context
-    has to be "polled" (e.g. via ca_pend_event or ca_pend_io). All callbacks
-    happen in the main thread.
-    ca_enable_preemptive_callback: EPICS creates a dedicated callback thread
-    where the callback is run.
-
-    Obviously, ca_enable_preemptive_callback is the variant we want for
-    subscription.
-    */
-    auto choice = ca_preemptive_callback_select::ca_disable_preemptive_callback;
-    if (subscribe) {
-        choice = ca_preemptive_callback_select::ca_enable_preemptive_callback;
-    }
-
     /*
     Try to create the Channel access context explicitly:
     https://docs.epics-controls.org/projects/base/en/latest/cadef_h.html#_CPPv417ca_context_create29ca_preemptive_callback_select
@@ -146,7 +131,8 @@ mEpicsCa<T>::mEpicsCa(const char *pChanName, bool subscribe,
     convertAndHandleEcaCode. Preemptive callbacks are disabled by default for
     this driver.
     */
-    status = ca_context_create(choice);
+    status = ca_context_create(
+        ca_preemptive_callback_select::ca_enable_preemptive_callback);
     if (status != ECA_NOTTHREADED) {
         status = convertAndHandleEcaCode(status, this->_chanName.c_str());
     }
@@ -490,7 +476,7 @@ template <typename T> int mEpicsCa<T>::putRaw(int *value) {
 
 template <typename T>
 void mEpicsCa<T>::connStateCallback(struct connection_handler_args args) {
-    mEpicsCa *self = static_cast<mEpicsCa *>(ca_puser(args.chid));
+    mEpicsCa<T> *self = static_cast<mEpicsCa<T> *>(ca_puser(args.chid));
 
     if (args.op == CA_OP_CONN_UP) {
         struct ChInfo info;

test/ioc/record.db

@@ -5,6 +5,10 @@ record(longin, "MEPICSCA:TEST:LONGIN") {
     field(PINI, "YES")
 }
 
+record(longout, "MEPICSCA:TEST:LONGOUT") {
+    field(VAL, 256)
+}
+
 record(ai, "MEPICSCA:TEST:AI") {
     field(VAL, 84)
 }

test/m_epics_ca_test.cxx

@@ -102,6 +102,7 @@ int main() {
     // interact with the spawned IOC.
     auto int_ca = mEpicsCa<int>("MEPICSCA:TEST:LONGIN", false);
     auto int_hopr_ca = mEpicsCa<int>("MEPICSCA:TEST:LONGIN.HOPR", false);
+    auto int_longout_ca = mEpicsCa<int>("MEPICSCA:TEST:LONGOUT", false);
     auto double_ca = mEpicsCa<double>("MEPICSCA:TEST:AI", false);
     auto string_ca = mEpicsCa<std::string>("MEPICSCA:TEST:STRINGIN", false);
     auto waveform_ca = mEpicsCa<std::string>("MEPICSCA:TEST:WAVEFORM", false);
@@ -198,6 +199,12 @@ int main() {
             EQUAL(status, CM_SUCCESS);
             EQUAL(int_val, 100);
 
+            // Read an integer from a longout
+            int_val = 0;
+            status = int_longout_ca.get(&int_val);
+            EQUAL(status, CM_SUCCESS);
+            EQUAL(int_val, 256);
+
             // Read a double from a record
             double double_val = 0.0;
             status = double_ca.get(&double_val);