fixes #316 nni_aio_set_synch() usually doesn't do anything

2 files changed, 19 insertions, 4 deletions

diff --git a/docs/man/nng_aio_stop.3.adoc b/docs/man/nng_aio_stop.3.adoc
index 5e65b8f7..02c258f8 100644
--- a/docs/man/nng_aio_stop.3.adoc
+++ b/docs/man/nng_aio_stop.3.adoc
@@ -28,9 +28,16 @@ The `nng_aio_stop()` function stops the asynchronous I/O operation
 associated with _aio_ by aborting with `NNG_ECANCELED`, and then waits
 for it to complete or to be completely aborted.
 
-This is logically the equivalent of <<nng_aio_cancel.3#,`nng_aio_cancel()`>>
-followed by <<nng_aio_wait.3#,`nng_aio_wait()`>>, except that the asynchronous
-I/O handle may not be used for any further operations.
+If an operation is in progress when this function is called, that operation
+is canceled and the callback function is _not_ allowed to run.
+
+If the callback function is already running when this function is called,
+then it is allowed to complete before returning to the caller.
+
+No new operations will be started on this _aio_.
+
+NOTE: Calling this function means that the operation may be aborted without
+completing its callback function.
 
 TIP: When multiple asynchronous I/O handles are in use and need to be
 shut down, it is safest to stop all of them, before deallocating any of
diff --git a/src/core/aio.c b/src/core/aio.c
index 1aaffe12..f3af80d8 100644
--- a/src/core/aio.c
+++ b/src/core/aio.c
@@ -392,7 +392,15 @@ nni_aio_finish_impl(nni_aio *aio, int rv, size_t count, nni_msg *msg)
 			aio->a_waiting = 0;
 			nni_cv_wake(&aio->a_cv);
 		}
-		nni_task_dispatch(&aio->a_task);
+
+		if (!aio->a_synch) {
+			nni_task_dispatch(&aio->a_task);
+		} else {
+			nni_mtx_unlock(&nni_aio_lk);
+			aio->a_task.task_cb(aio->a_task.task_arg);
+			nni_mtx_lock(&nni_aio_lk);
+			aio->a_synch = 0;
+		}
 	}
 	nni_mtx_unlock(&nni_aio_lk);
 }