Implement H5ESget requests function to retrieve requests from an event set (#1355)

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

7 files changed, 659 insertions, 18 deletions

diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index fc7d4dd..d059fb3 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -516,6 +516,13 @@ New Features
 
     Library:
     --------
+    - Add a new public function, H5ESget_requests()
+
+      This function allows the user to retrieve request pointers from an event
+      set. It is intended for use primarily by VOL plug in developers.
+
+      (NAF - 2022/01/11)
+
     - Adds new file driver-level memory copy operation for
       "ctl" callback and updates compact dataset I/O routines
       to utilize it
diff --git a/src/H5ES.c b/src/H5ES.c
index ccc0dd8..9abaa54 100644
--- a/src/H5ES.c
+++ b/src/H5ES.c
@@ -236,6 +236,61 @@ done:
 } /* end H5ESget_op_counter() */
 
 /*-------------------------------------------------------------------------
+ * Function:    H5ESget_requests
+ *
+ * Purpose:     Retrieve the requests in an event set.  Up to *count
+ *              requests are stored in the provided requests array, and
+ *              the connector ids corresponding to these requests are
+ *              stored in the provided connector_ids array.  Either or
+ *              both of these arrays may be NULL, in which case this
+ *              information is not returned.  If these arrays are
+ *              non-NULL, they must be large enough to contain *count
+ *              entries.  On exit, *count is set to the total number of
+ *              events in the event set.
+ *
+ *              Events are returned in the order they were added to the
+ *              event set.  If order is H5_ITER_INC or H5_ITER_NATIVE,
+ *              events will be returned starting from the oldest. If order
+ *              is H5_ITER_DEC, events will be returned starting with the
+ *              newest/most recent.
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:  Neil Fortner
+ *              Tuesday, November 23, 2021
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5ESget_requests(hid_t es_id, H5_iter_order_t order, hid_t *connector_ids, void **requests, size_t array_len,
+                 size_t *count /*out*/)
+{
+    H5ES_t *es;                  /* Event set */
+    herr_t  ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE5("e", "iIo*i**xx", es_id, order, connector_ids, requests, count);
+
+    /* Check arguments */
+    if (NULL == (es = H5I_object_verify(es_id, H5I_EVENTSET)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid event set identifier")
+    if (order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")
+
+    /* Call internal routine */
+    if (array_len > 0 && (requests || connector_ids))
+        if (H5ES__get_requests(es, order, connector_ids, requests, array_len) < 0)
+            HGOTO_ERROR(H5E_EVENTSET, H5E_CANTGET, FAIL, "can't get requests")
+
+    /* Retrieve the count, if non-NULL */
+    if (count)
+        *count = H5ES__list_count(&es->active);
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5ESget_requests() */
+
+/*-------------------------------------------------------------------------
  * Function:    H5ESwait
  *
  * Purpose:     Wait (with timeout) for operations in event set to complete
diff --git a/src/H5ESdevelop.h b/src/H5ESdevelop.h
index 5a0f2b4..2fb9aeb 100644
--- a/src/H5ESdevelop.h
+++ b/src/H5ESdevelop.h
@@ -42,6 +42,8 @@ extern "C" {
 #endif
 
 H5_DLL herr_t H5ESinsert_request(hid_t es_id, hid_t connector_id, void *request);
+H5_DLL herr_t H5ESget_requests(hid_t es_id, H5_iter_order_t order, hid_t *connector_ids, void **requests,
+                               size_t array_len, size_t *count);
 
 #ifdef __cplusplus
 }
diff --git a/src/H5ESint.c b/src/H5ESint.c
index c66be16..7eb5909 100644
--- a/src/H5ESint.c
+++ b/src/H5ESint.c
@@ -50,6 +50,14 @@
 /* Local Typedefs */
 /******************/
 
+/* Callback context for get events operations */
+typedef struct H5ES_get_requests_ctx_t {
+    hid_t *connector_ids; /* Output buffer for list of connector IDs that match the above requests */
+    void **requests;      /* Output buffer for list of requests in event set */
+    size_t array_len;     /* Length of the above output buffers */
+    size_t i;             /* Number of elements filled in output buffers */
+} H5ES_get_requests_ctx_t;
+
 /* Callback context for wait operations */
 typedef struct H5ES_wait_ctx_t {
     H5ES_t * es;              /* Event set being operated on */
@@ -84,6 +92,7 @@ static herr_t H5ES__close(H5ES_t *es);
 static herr_t H5ES__close_cb(void *es, void **request_token);
 static herr_t H5ES__insert(H5ES_t *es, H5VL_t *connector, void *request_token, const char *app_file,
                            const char *app_func, unsigned app_line, const char *caller, const char *api_args);
+static int    H5ES__get_requests_cb(H5ES_event_t *ev, void *_ctx);
 static herr_t H5ES__handle_fail(H5ES_t *es, H5ES_event_t *ev);
 static herr_t H5ES__op_complete(H5ES_t *es, H5ES_event_t *ev, H5VL_request_status_t ev_status);
 static int    H5ES__wait_cb(H5ES_event_t *ev, void *_ctx);
@@ -282,7 +291,8 @@ H5ES__insert(H5ES_t *es, H5VL_t *connector, void *request_token, const char *app
      * there's no need to duplicate it.
      */
     ev->op_info.api_name = caller;
-    if (NULL == (ev->op_info.api_args = H5MM_xstrdup(api_args)))
+    HDassert(ev->op_info.api_args == NULL);
+    if (api_args && NULL == (ev->op_info.api_args = H5MM_xstrdup(api_args)))
         HGOTO_ERROR(H5E_EVENTSET, H5E_CANTALLOC, FAIL, "can't copy API routine arguments")
 
     /* Append fully initialized event onto the event set's 'active' list */
@@ -419,6 +429,86 @@ done:
 } /* end H5ES__insert_request() */
 
 /*-------------------------------------------------------------------------
+ * Function:    H5ES__get_requests_cb
+ *
+ * Purpose:     Iterator callback for H5ES__get_events - adds the event to
+ *              the list.
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:  Neil Fortner
+ *              Tuesday, November 23, 2021
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5ES__get_requests_cb(H5ES_event_t *ev, void *_ctx)
+{
+    H5ES_get_requests_ctx_t *ctx       = (H5ES_get_requests_ctx_t *)_ctx; /* Callback context */
+    int                      ret_value = H5_ITER_CONT;                    /* Return value */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity check */
+    HDassert(ev);
+    HDassert(ctx);
+    HDassert(ctx->i < ctx->array_len);
+
+    /* Get the connector ID for the event */
+    if (ctx->connector_ids)
+        ctx->connector_ids[ctx->i] = ev->request->connector->id;
+
+    /* Get the request for the event */
+    if (ctx->requests)
+        ctx->requests[ctx->i] = ev->request->data;
+
+    /* Check if we've run out of room in the arrays */
+    if (++ctx->i == ctx->array_len)
+        ret_value = H5_ITER_STOP;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5ES__get_requests_cb() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5ES__get_requests
+ *
+ * Purpose:     Get all requests in an event set.
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:  Neil Fortner
+ *              Tuesday, November 23, 2021
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5ES__get_requests(H5ES_t *es, H5_iter_order_t order, hid_t *connector_ids, void **requests, size_t array_len)
+{
+    H5ES_get_requests_ctx_t ctx;                 /* Callback context */
+    herr_t                  ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Sanity check */
+    HDassert(es);
+    HDassert(array_len > 0);
+    HDassert(requests || connector_ids);
+
+    /* Set up context for iterator callbacks */
+    ctx.connector_ids = connector_ids;
+    ctx.requests      = requests;
+    ctx.array_len     = array_len;
+    ctx.i             = 0;
+
+    /* Iterate over the events in the set */
+    if (H5ES__list_iterate(&es->active, order, H5ES__get_requests_cb, &ctx) < 0)
+        HGOTO_ERROR(H5E_EVENTSET, H5E_BADITER, FAIL, "iteration failed")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5ES__get_requests() */
+
+/*-------------------------------------------------------------------------
  * Function:    H5ES__handle_fail
  *
  * Purpose:     Handle a failed event
@@ -661,7 +751,7 @@ H5ES__wait(H5ES_t *es, uint64_t timeout, size_t *num_in_progress, hbool_t *op_fa
     ctx.op_failed       = op_failed;
 
     /* Iterate over the events in the set, waiting for them to complete */
-    if (H5ES__list_iterate(&es->active, H5ES__wait_cb, &ctx) < 0)
+    if (H5ES__list_iterate(&es->active, H5_ITER_NATIVE, H5ES__wait_cb, &ctx) < 0)
         HGOTO_ERROR(H5E_EVENTSET, H5E_BADITER, FAIL, "iteration failed")
 
 done:
@@ -769,7 +859,7 @@ H5ES__cancel(H5ES_t *es, size_t *num_not_canceled, hbool_t *op_failed)
     ctx.op_failed        = op_failed;
 
     /* Iterate over the events in the set, attempting to cancel them */
-    if (H5ES__list_iterate(&es->active, H5ES__cancel_cb, &ctx) < 0)
+    if (H5ES__list_iterate(&es->active, H5_ITER_NATIVE, H5ES__cancel_cb, &ctx) < 0)
         HGOTO_ERROR(H5E_EVENTSET, H5E_BADITER, FAIL, "iteration failed")
 
 done:
@@ -806,13 +896,13 @@ H5ES__get_err_info_cb(H5ES_event_t *ev, void *_ctx)
      * so there's no need to duplicate them internally, but they are duplicated
      * here, when they are given back to the user.
      */
-    if (NULL == (ctx->curr_err_info->api_name = H5MM_strdup(ev->op_info.api_name)))
+    if (NULL == (ctx->curr_err_info->api_name = H5MM_xstrdup(ev->op_info.api_name)))
         HGOTO_ERROR(H5E_EVENTSET, H5E_CANTALLOC, H5_ITER_ERROR, "can't copy HDF5 API routine name")
-    if (NULL == (ctx->curr_err_info->api_args = H5MM_strdup(ev->op_info.api_args)))
+    if (NULL == (ctx->curr_err_info->api_args = H5MM_xstrdup(ev->op_info.api_args)))
         HGOTO_ERROR(H5E_EVENTSET, H5E_CANTALLOC, H5_ITER_ERROR, "can't copy HDF5 API routine arguments")
-    if (NULL == (ctx->curr_err_info->app_file_name = H5MM_strdup(ev->op_info.app_file_name)))
+    if (NULL == (ctx->curr_err_info->app_file_name = H5MM_xstrdup(ev->op_info.app_file_name)))
         HGOTO_ERROR(H5E_EVENTSET, H5E_CANTALLOC, H5_ITER_ERROR, "can't copy HDF5 application file name")
-    if (NULL == (ctx->curr_err_info->app_func_name = H5MM_strdup(ev->op_info.app_func_name)))
+    if (NULL == (ctx->curr_err_info->app_func_name = H5MM_xstrdup(ev->op_info.app_func_name)))
         HGOTO_ERROR(H5E_EVENTSET, H5E_CANTALLOC, H5_ITER_ERROR, "can't copy HDF5 application function name")
     ctx->curr_err_info->app_line_num = ev->op_info.app_line_num;
     ctx->curr_err_info->op_ins_count = ev->op_info.op_ins_count;
@@ -883,7 +973,7 @@ H5ES__get_err_info(H5ES_t *es, size_t num_err_info, H5ES_err_info_t err_info[],
     ctx.curr_err_info = &err_info[0];
 
     /* Iterate over the failed events in the set, copying their error info */
-    if (H5ES__list_iterate(&es->failed, H5ES__get_err_info_cb, &ctx) < 0)
+    if (H5ES__list_iterate(&es->failed, H5_ITER_NATIVE, H5ES__get_err_info_cb, &ctx) < 0)
         HGOTO_ERROR(H5E_EVENTSET, H5E_BADITER, FAIL, "iteration failed")
 
     /* Set # of failed events cleared from event set's failed list */
@@ -957,7 +1047,7 @@ H5ES__close(H5ES_t *es)
             "can't close event set while unfinished operations are present (i.e. wait on event set first)")
 
     /* Iterate over the failed events in the set, releasing them */
-    if (H5ES__list_iterate(&es->failed, H5ES__close_failed_cb, (void *)es) < 0)
+    if (H5ES__list_iterate(&es->failed, H5_ITER_NATIVE, H5ES__close_failed_cb, (void *)es) < 0)
         HGOTO_ERROR(H5E_EVENTSET, H5E_BADITER, FAIL, "iteration failed")
 
     /* Release the event set */
diff --git a/src/H5ESlist.c b/src/H5ESlist.c
index 3180322..61a9dd1 100644
--- a/src/H5ESlist.c
+++ b/src/H5ESlist.c
@@ -135,7 +135,10 @@ H5ES__list_count(const H5ES_event_list_t *el)
  *              each event.
  *
  * Note:        Iteration is safe for deleting the current event.  Modifying
- *              the list in other ways is likely unsafe.
+ *              the list in other ways is likely unsafe.  If order is
+ *              H5_ITER_INC or H5_ITER_NATIVE events are visited starting
+ *              with the oldest, otherwise they are visited starting with
+ *              the newest.
  *
  * Return:      SUCCEED / FAIL
  *
@@ -145,7 +148,7 @@ H5ES__list_count(const H5ES_event_list_t *el)
  *-------------------------------------------------------------------------
  */
 int
-H5ES__list_iterate(H5ES_event_list_t *el, H5ES_list_iter_func_t cb, void *ctx)
+H5ES__list_iterate(H5ES_event_list_t *el, H5_iter_order_t order, H5ES_list_iter_func_t cb, void *ctx)
 {
     H5ES_event_t *ev;                       /* Event in list */
     int           ret_value = H5_ITER_CONT; /* Return value */
@@ -157,12 +160,12 @@ H5ES__list_iterate(H5ES_event_list_t *el, H5ES_list_iter_func_t cb, void *ctx)
     HDassert(cb);
 
     /* Iterate over events in list */
-    ev = el->head;
+    ev = (order == H5_ITER_DEC) ? el->tail : el->head;
     while (ev) {
         H5ES_event_t *tmp; /* Temporary event */
 
         /* Get pointer to next node, so it's safe if this one is removed */
-        tmp = ev->next;
+        tmp = (order == H5_ITER_DEC) ? ev->prev : ev->next;
 
         /* Perform iterator callback */
         if ((ret_value = (*cb)(ev, ctx)) != H5_ITER_CONT) {
diff --git a/src/H5ESpkg.h b/src/H5ESpkg.h
index a7a8e20..6ee50fa 100644
--- a/src/H5ESpkg.h
+++ b/src/H5ESpkg.h
@@ -81,6 +81,8 @@ typedef int (*H5ES_list_iter_func_t)(H5ES_event_t *ev, void *ctx);
 H5_DLL H5ES_t *H5ES__create(void);
 H5_DLL herr_t  H5ES__insert_request(H5ES_t *es, H5VL_t *connector, void *token);
 H5_DLL herr_t  H5ES__wait(H5ES_t *es, uint64_t timeout, size_t *num_in_progress, hbool_t *op_failed);
+H5_DLL herr_t  H5ES__get_requests(H5ES_t *es, H5_iter_order_t order, hid_t *connector_ids, void **requests,
+                                  size_t array_len);
 H5_DLL herr_t  H5ES__cancel(H5ES_t *es, size_t *num_not_canceled, hbool_t *op_failed);
 H5_DLL herr_t  H5ES__get_err_info(H5ES_t *es, size_t num_err_info, H5ES_err_info_t err_info[],
                                   size_t *num_cleared);
@@ -88,7 +90,8 @@ H5_DLL herr_t  H5ES__get_err_info(H5ES_t *es, size_t num_err_info, H5ES_err_info
 /* Event list operations */
 H5_DLL void   H5ES__list_append(H5ES_event_list_t *el, H5ES_event_t *ev);
 H5_DLL size_t H5ES__list_count(const H5ES_event_list_t *el);
-H5_DLL int    H5ES__list_iterate(H5ES_event_list_t *el, H5ES_list_iter_func_t cb, void *ctx);
+H5_DLL int    H5ES__list_iterate(H5ES_event_list_t *el, H5_iter_order_t order, H5ES_list_iter_func_t cb,
+                                 void *ctx);
 H5_DLL void   H5ES__list_remove(H5ES_event_list_t *el, const H5ES_event_t *ev);
 
 /* Event operations */
diff --git a/test/event_set.c b/test/event_set.c
index 5df49e9..22df510 100644
--- a/test/event_set.c
+++ b/test/event_set.c
@@ -19,8 +19,157 @@
 #include "h5test.h"
 #include "H5srcdir.h"
 
+#define EVENT_SET_NUM_CONNECTOR_IDS 2
+
 const char *FILENAME[] = {"event_set_1", NULL};
 
+hid_t connector_ids_g[EVENT_SET_NUM_CONNECTOR_IDS];
+
+herr_t fake_wait_request_wait(void *req, uint64_t timeout, H5VL_request_status_t *status);
+herr_t fake_wait_request_free(void *req);
+
+/* A VOL class struct that describes a VOL class with no
+ * functionality, other than a wait that returns success.
+ */
+static const H5VL_class_t fake_wait_vol_g = {
+    H5VL_VERSION,              /* VOL class struct version */
+    ((H5VL_class_value_t)501), /* value        */
+    "fake_wait",               /* name         */
+    0,                         /* connector version */
+    0,                         /* capability flags */
+    NULL,                      /* initialize   */
+    NULL,                      /* terminate    */
+    {
+        /* info_cls */
+        (size_t)0, /* size    */
+        NULL,      /* copy    */
+        NULL,      /* compare */
+        NULL,      /* free    */
+        NULL,      /* to_str  */
+        NULL,      /* from_str */
+    },
+    {
+        /* wrap_cls */
+        NULL, /* get_object   */
+        NULL, /* get_wrap_ctx */
+        NULL, /* wrap_object  */
+        NULL, /* unwrap_object */
+        NULL, /* free_wrap_ctx */
+    },
+    {
+        /* attribute_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* read         */
+        NULL, /* write        */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
+    },
+    {
+        /* dataset_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* read         */
+        NULL, /* write        */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
+    },
+    {
+        /* datatype_cls */
+        NULL, /* commit       */
+        NULL, /* open         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
+    },
+    {
+        /* file_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
+    },
+    {
+        /* group_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
+    },
+    {
+        /* link_cls */
+        NULL, /* create       */
+        NULL, /* copy         */
+        NULL, /* move         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL  /* optional     */
+    },
+    {
+        /* object_cls */
+        NULL, /* open         */
+        NULL, /* copy         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL  /* optional     */
+    },
+    {
+        /* introspect_cls */
+        NULL, /* get_conn_cls */
+        NULL, /* get_cap_flags */
+        NULL, /* opt_query    */
+    },
+    {
+        /* request_cls */
+        fake_wait_request_wait, /* wait         */
+        NULL,                   /* notify       */
+        NULL,                   /* cancel       */
+        NULL,                   /* specific     */
+        NULL,                   /* optional     */
+        fake_wait_request_free  /* free         */
+    },
+    {
+        /* blob_cls */
+        NULL, /* put          */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL  /* optional     */
+    },
+    {
+        /* token_cls */
+        NULL, /* cmp              */
+        NULL, /* to_str           */
+        NULL  /* from_str         */
+    },
+    NULL /* optional     */
+};
+
+herr_t
+fake_wait_request_wait(void H5_ATTR_UNUSED *req, uint64_t H5_ATTR_UNUSED timeout,
+                       H5VL_request_status_t *status)
+{
+    /* Set status if requested */
+    if (status)
+        *status = H5VL_REQUEST_STATUS_SUCCEED;
+
+    return 0;
+} /* end H5_daos_req_wait() */
+
+herr_t
+fake_wait_request_free(void H5_ATTR_UNUSED *req)
+{
+    return 0;
+} /* end fake_wait_request_free() */
+
 /*-------------------------------------------------------------------------
  * Function:    test_es_create
  *
@@ -159,6 +308,324 @@ error:
 }
 
 /*-------------------------------------------------------------------------
+ * Function:    test_es_get_requests
+ *
+ * Purpose:     Tests getting requests from event set.
+ *
+ * Return:      Success:    0
+ *              Failure:    number of errors
+ *
+ * Programmer:  Neil Fortner
+ *              Wednesday, November 24, 2021
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+test_es_get_requests(void)
+{
+    hid_t   es_id;            /* Event set ID */
+    hid_t   connector_ids[2]; /* Connector IDs */
+    void *  requests[2];      /* Requests */
+    int     req_targets[2];   /* Dummy targets for void * requests */
+    size_t  count;            /* # of events in set */
+    hbool_t op_failed;        /* Whether an operation failed (unused) */
+
+    TESTING("event set get requests");
+
+    /* Create an event set */
+    if ((es_id = H5EScreate()) < 0)
+        TEST_ERROR
+
+    /* Get number of requests in event set */
+    count = 3;
+    if (H5ESget_requests(es_id, H5_ITER_NATIVE, NULL, NULL, 0, &count) < 0)
+        TEST_ERROR
+    if (count != 0)
+        TEST_ERROR
+
+    /* Get only connector IDs */
+    count = 3;
+    if (H5ESget_requests(es_id, H5_ITER_NATIVE, connector_ids, NULL, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 0)
+        TEST_ERROR
+
+    /* Get only requests */
+    count = 3;
+    if (H5ESget_requests(es_id, H5_ITER_NATIVE, NULL, requests, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 0)
+        TEST_ERROR
+
+    /* Get both */
+    count = 3;
+    if (H5ESget_requests(es_id, H5_ITER_NATIVE, connector_ids, requests, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 0)
+        TEST_ERROR
+
+    /* Insert event into event set */
+    if (H5ESinsert_request(es_id, connector_ids_g[0], &req_targets[0]) < 0)
+        TEST_ERROR
+
+    /* Get number of requests in event set */
+    count = 0;
+    if (H5ESget_requests(es_id, H5_ITER_NATIVE, NULL, NULL, 0, &count) < 0)
+        TEST_ERROR
+    if (count != 1)
+        TEST_ERROR
+
+    /* Get only connector IDs */
+    count            = 0;
+    connector_ids[0] = H5I_INVALID_HID;
+    connector_ids[1] = H5I_INVALID_HID;
+    if (H5ESget_requests(es_id, H5_ITER_NATIVE, connector_ids, NULL, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 1)
+        TEST_ERROR
+    if (connector_ids[0] != connector_ids_g[0])
+        TEST_ERROR
+    if (connector_ids[1] != H5I_INVALID_HID)
+        TEST_ERROR
+
+    /* Get only requests */
+    count       = 0;
+    requests[0] = NULL;
+    requests[1] = NULL;
+    if (H5ESget_requests(es_id, H5_ITER_NATIVE, NULL, requests, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 1)
+        TEST_ERROR
+    if (requests[0] != &req_targets[0])
+        TEST_ERROR
+    if (requests[1] != NULL)
+        TEST_ERROR
+
+    /* Get both */
+    count            = 0;
+    connector_ids[0] = H5I_INVALID_HID;
+    connector_ids[1] = H5I_INVALID_HID;
+    requests[0]      = NULL;
+    requests[1]      = NULL;
+    if (H5ESget_requests(es_id, H5_ITER_NATIVE, connector_ids, requests, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 1)
+        TEST_ERROR
+    if (connector_ids[0] != connector_ids_g[0])
+        TEST_ERROR
+    if (connector_ids[1] != H5I_INVALID_HID)
+        TEST_ERROR
+    if (requests[0] != &req_targets[0])
+        TEST_ERROR
+    if (requests[1] != NULL)
+        TEST_ERROR
+
+    /* Insert second event into event set */
+    if (H5ESinsert_request(es_id, connector_ids_g[1], &req_targets[1]) < 0)
+        TEST_ERROR
+
+    /* Get number of requests in event set */
+    count = 0;
+    if (H5ESget_requests(es_id, H5_ITER_NATIVE, NULL, NULL, 0, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+
+    /* Get only connector IDs */
+    count            = 0;
+    connector_ids[0] = H5I_INVALID_HID;
+    connector_ids[1] = H5I_INVALID_HID;
+    if (H5ESget_requests(es_id, H5_ITER_INC, connector_ids, NULL, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+    if (connector_ids[0] != connector_ids_g[0])
+        TEST_ERROR
+    if (connector_ids[1] != connector_ids_g[1])
+        TEST_ERROR
+
+    /* Try with H5_ITER_DEC */
+    count            = 0;
+    connector_ids[0] = H5I_INVALID_HID;
+    connector_ids[1] = H5I_INVALID_HID;
+    if (H5ESget_requests(es_id, H5_ITER_DEC, connector_ids, NULL, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+    if (connector_ids[0] != connector_ids_g[1])
+        TEST_ERROR
+    if (connector_ids[1] != connector_ids_g[0])
+        TEST_ERROR
+
+    /* Get only requests */
+    count       = 0;
+    requests[0] = NULL;
+    requests[1] = NULL;
+    if (H5ESget_requests(es_id, H5_ITER_INC, NULL, requests, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+    if (requests[0] != &req_targets[0])
+        TEST_ERROR
+    if (requests[1] != &req_targets[1])
+        TEST_ERROR
+
+    /* Try with H5_ITER_DEC */
+    count       = 0;
+    requests[0] = NULL;
+    requests[1] = NULL;
+    if (H5ESget_requests(es_id, H5_ITER_DEC, NULL, requests, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+    if (requests[0] != &req_targets[1])
+        TEST_ERROR
+    if (requests[1] != &req_targets[0])
+        TEST_ERROR
+
+    /* Get both */
+    count            = 0;
+    connector_ids[0] = H5I_INVALID_HID;
+    connector_ids[1] = H5I_INVALID_HID;
+    requests[0]      = NULL;
+    requests[1]      = NULL;
+    if (H5ESget_requests(es_id, H5_ITER_INC, connector_ids, requests, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+    if (connector_ids[0] != connector_ids_g[0])
+        TEST_ERROR
+    if (connector_ids[1] != connector_ids_g[1])
+        TEST_ERROR
+    if (requests[0] != &req_targets[0])
+        TEST_ERROR
+    if (requests[1] != &req_targets[1])
+        TEST_ERROR
+
+    /* Try with H5_ITER_DEC */
+    count            = 0;
+    connector_ids[0] = H5I_INVALID_HID;
+    connector_ids[1] = H5I_INVALID_HID;
+    requests[0]      = NULL;
+    requests[1]      = NULL;
+    if (H5ESget_requests(es_id, H5_ITER_DEC, connector_ids, requests, 2, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+    if (connector_ids[0] != connector_ids_g[1])
+        TEST_ERROR
+    if (connector_ids[1] != connector_ids_g[0])
+        TEST_ERROR
+    if (requests[0] != &req_targets[1])
+        TEST_ERROR
+    if (requests[1] != &req_targets[0])
+        TEST_ERROR
+
+    /* Get only first connector ID */
+    count            = 0;
+    connector_ids[0] = H5I_INVALID_HID;
+    connector_ids[1] = H5I_INVALID_HID;
+    if (H5ESget_requests(es_id, H5_ITER_INC, connector_ids, NULL, 1, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+    if (connector_ids[0] != connector_ids_g[0])
+        TEST_ERROR
+    if (connector_ids[1] != H5I_INVALID_HID)
+        TEST_ERROR
+
+    /* Try with H5_ITER_DEC */
+    count            = 0;
+    connector_ids[0] = H5I_INVALID_HID;
+    connector_ids[1] = H5I_INVALID_HID;
+    if (H5ESget_requests(es_id, H5_ITER_DEC, connector_ids, NULL, 1, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+    if (connector_ids[0] != connector_ids_g[1])
+        TEST_ERROR
+    if (connector_ids[1] != H5I_INVALID_HID)
+        TEST_ERROR
+
+    /* Get only first request */
+    count       = 0;
+    requests[0] = NULL;
+    requests[1] = NULL;
+    if (H5ESget_requests(es_id, H5_ITER_INC, NULL, requests, 1, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+    if (requests[0] != &req_targets[0])
+        TEST_ERROR
+    if (requests[1] != NULL)
+        TEST_ERROR
+
+    /* Try with H5_ITER_DEC */
+    count       = 0;
+    requests[0] = NULL;
+    requests[1] = NULL;
+    if (H5ESget_requests(es_id, H5_ITER_DEC, NULL, requests, 1, &count) < 0)
+        TEST_ERROR
+    if (count != 2)
+        TEST_ERROR
+    if (requests[0] != &req_targets[1])
+        TEST_ERROR
+    if (requests[1] != NULL)
+        TEST_ERROR
+
+    /* Get only first of both */
+    count            = 0;
+    connector_ids[0] = H5I_INVALID_HID;
+    connector_ids[1] = H5I_INVALID_HID;
+    requests[0]      = NULL;
+    requests[1]      = NULL;
+    if (H5ESget_requests(es_id, H5_ITER_INC, connector_ids, requests, 1, &count) < 0)
+        TEST_ERROR
+    if (connector_ids[0] != connector_ids_g[0])
+        TEST_ERROR
+    if (connector_ids[1] != H5I_INVALID_HID)
+        TEST_ERROR
+    if (requests[0] != &req_targets[0])
+        TEST_ERROR
+    if (requests[1] != NULL)
+        TEST_ERROR
+
+    /* Try with H5_ITER_DEC */
+    count            = 0;
+    connector_ids[0] = H5I_INVALID_HID;
+    connector_ids[1] = H5I_INVALID_HID;
+    requests[0]      = NULL;
+    requests[1]      = NULL;
+    if (H5ESget_requests(es_id, H5_ITER_DEC, connector_ids, requests, 1, &count) < 0)
+        TEST_ERROR
+    if (connector_ids[0] != connector_ids_g[1])
+        TEST_ERROR
+    if (connector_ids[1] != H5I_INVALID_HID)
+        TEST_ERROR
+    if (requests[0] != &req_targets[1])
+        TEST_ERROR
+    if (requests[1] != NULL)
+        TEST_ERROR
+
+    /* Close the event set */
+    if (H5ESwait(es_id, 10000000, &count, &op_failed) < 0)
+        TEST_ERROR
+    if (H5ESclose(es_id) < 0)
+        TEST_ERROR
+
+    PASSED();
+    return 0;
+
+error:
+    H5E_BEGIN_TRY
+    {
+        H5ESclose(es_id);
+    }
+    H5E_END_TRY;
+    return 1;
+}
+
+/*-------------------------------------------------------------------------
  * Function:    main
  *
  * Purpose:     Tests event sets
@@ -175,27 +642,41 @@ int
 main(void)
 {
     hid_t fapl_id = H5I_INVALID_HID; /* File access property list */
+    int   i;                         /* Local index variable */
     int   nerrors = 0;               /* Error count */
 
     /* Setup */
     h5_reset();
     fapl_id = h5_fileaccess();
 
+    /* Register dummy connector IDs */
+    for (i = 0; i < EVENT_SET_NUM_CONNECTOR_IDS; i++)
+        if ((connector_ids_g[i] = H5VLregister_connector(&fake_wait_vol_g, H5P_DEFAULT)) < 0)
+            TEST_ERROR
+
     /* Tests */
     nerrors += test_es_create();
     nerrors += test_es_none();
+    nerrors += test_es_get_requests();
+
+    /* Unregister dummy connectors */
+    for (i = 0; i < EVENT_SET_NUM_CONNECTOR_IDS; i++)
+        if (H5VLunregister_connector(connector_ids_g[i]) < 0)
+            TEST_ERROR
 
     /* Cleanup */
     h5_cleanup(FILENAME, fapl_id);
 
     /* Check for any errors */
-    if (nerrors) {
-        HDputs("***** EVENT SET TESTS FAILED *****");
-        HDexit(EXIT_FAILURE);
-    } /* end if */
+    if (nerrors)
+        goto error;
 
     /* Report status */
     HDputs("All event set tests passed.");
 
     HDexit(EXIT_SUCCESS);
+
+error:
+    HDputs("***** EVENT SET TESTS FAILED *****");
+    HDexit(EXIT_FAILURE);
 } /* end main() */