modified margo_get_handler_pool to prevent users from changing pool

examples/composition/composed-svc-daemon.c

@@ -56,7 +56,7 @@ int main(int argc, char **argv)
     hg_addr_t addr_self;
     char addr_self_string[128];
     hg_size_t addr_self_string_sz = 128;
-    ABT_pool *handler_pool;
+    ABT_pool handler_pool;
     char* svc_list;
     char* svc;
 
@@ -109,17 +109,17 @@ int main(int argc, char **argv)
      */
     MARGO_REGISTER(mid, "my_shutdown_rpc", void, void, my_rpc_shutdown_ult);
 
-    handler_pool = margo_get_handler_pool(mid);
+    margo_get_handler_pool(mid, &handler_pool);
     svc = strtok(svc_list, ",");
     while(svc)
     {
         if(!strcmp(svc, "data-xfer"))
         {
-            data_xfer_service_register(mid, *handler_pool, 0);
+            data_xfer_service_register(mid, handler_pool, 0);
         }
         else if(!strcmp(svc, "delegator"))
         {
-            delegator_service_register(mid, *handler_pool, 0);
+            delegator_service_register(mid, handler_pool, 0);
         }
         else
             assert(0);

examples/multiplex/margo-example-mp-server.c

@@ -59,7 +59,7 @@ int main(int argc, char **argv)
     hg_size_t addr_self_string_sz = 128;
     ABT_xstream svc1_xstream2;
     ABT_pool svc1_pool2;
-    ABT_pool *handler_pool;
+    ABT_pool handler_pool;
 
     if(argc != 2)
     {
@@ -110,8 +110,8 @@ int main(int argc, char **argv)
     /* register svc1, with mplex_id 1, to execute on the default handler pool
      * used by Margo
      */
-    handler_pool = margo_get_handler_pool(mid);
-    ret = svc1_register(mid, *handler_pool, 1);
+    margo_get_handler_pool(mid, &handler_pool);
+    ret = svc1_register(mid, handler_pool, 1);
     assert(ret == 0);
 
     /* create a dedicated xstream and pool for another instance of svc1 */
@@ -134,8 +134,8 @@ int main(int argc, char **argv)
     /* register svc2, with mplex_id 3, to execute on the default handler pool
      * used by Margo
      */
-    handler_pool = margo_get_handler_pool(mid);
-    ret = svc2_register(mid, *handler_pool, 3);
+    margo_get_handler_pool(mid, &handler_pool);
+    ret = svc2_register(mid, handler_pool, 3);
     assert(ret == 0);
 
     /* shut things down */

include/margo.h

@@ -711,8 +711,10 @@ void margo_thread_sleep(
  * Retrieve the abt_handler pool that was associated with the instance at 
  *    initialization time
  * @param [in] mid Margo instance
+ * @param [out] pool handler pool
+ * @return 0 on success, error code on failure
  */
-ABT_pool* margo_get_handler_pool(margo_instance_id mid);
+int margo_get_handler_pool(margo_instance_id mid, ABT_pool* pool);
 
 /**
  * Retrieve the Mercury context that was associated with this instance at
@@ -836,7 +838,7 @@ hg_return_t __name##_handler(hg_handle_t handle) { \
         return(HG_INVALID_PARAM); \
     }\
     if(__pool == ABT_POOL_NULL) \
-        __pool = *margo_get_handler_pool(__mid); \
+        margo_get_handler_pool(__mid, &__pool); \
     __ret = ABT_thread_create(__pool, (void (*)(void *))__name, handle, ABT_THREAD_ATTR_NULL, NULL); \
     if(__ret != 0) { \
         return(HG_NOMEM_ERROR); \

src/margo-timer.c

@@ -142,7 +142,7 @@ void margo_check_timers(
     int ret;
     margo_timer_t *cur;
     struct margo_timer_instance *timer_inst;
-    ABT_pool *handler_pool;
+    ABT_pool handler_pool;
     double now = ABT_get_wtime();
 
     timer_inst = margo_get_timer_instance(mid);
@@ -160,10 +160,10 @@ void margo_check_timers(
         cur->prev = cur->next = NULL;
 
         /* schedule callback on the handler pool */
-        handler_pool = margo_get_handler_pool(mid);
-        if(*handler_pool != ABT_POOL_NULL)
+        margo_get_handler_pool(mid, &handler_pool);
+        if(handler_pool != ABT_POOL_NULL)
         {
-            ret = ABT_thread_create(*handler_pool, cur->cb_fn, cur->cb_dat,
+            ret = ABT_thread_create(handler_pool, cur->cb_fn, cur->cb_dat,
                 ABT_THREAD_ATTR_NULL, NULL);
             assert(ret == ABT_SUCCESS);
         }

src/margo.c

@@ -966,9 +966,14 @@ void margo_thread_sleep(
     return;
 }
 
-ABT_pool* margo_get_handler_pool(margo_instance_id mid)
+int margo_get_handler_pool(margo_instance_id mid, ABT_pool* pool)
 {
-    return(&mid->handler_pool);
+    if(mid) {
+        *pool = mid->handler_pool;
+        return 0;
+    } else {
+        return -1;
+    }
 }
 
 hg_context_t* margo_get_context(margo_instance_id mid)