diff --git a/nsock/include/nsock.h b/nsock/include/nsock.h
index e34f090e2..36f4a76eb 100644
--- a/nsock/include/nsock.h
+++ b/nsock/include/nsock.h
@@ -381,10 +381,13 @@ nsock_iod nsi_new2(nsock_pool nsockp, int sd, void *userdata);
  * notification to each event), NSOCK_PENDING_SILENT (do not send notification
  * to the killed events), or NSOCK_PENDING_ERROR (print an error message and
  * quit the program) */
-#define NSOCK_PENDING_NOTIFY 1
-#define NSOCK_PENDING_SILENT 2
-#define NSOCK_PENDING_ERROR 4
-void nsi_delete(nsock_iod nsockiod, int pending_response);
+enum nsock_del_mode {
+  NSOCK_PENDING_NOTIFY,
+  NSOCK_PENDING_SILENT,
+  NSOCK_PENDING_ERROR,
+};
+
+void nsi_delete(nsock_iod nsockiod, enum nsock_del_mode pending_response);
 
 /* Sometimes it is useful to store a pointer to information inside
  * the nsiod so you can retrieve it during a callback. */
diff --git a/nsock/src/nsock_iod.c b/nsock/src/nsock_iod.c
index 935eea0b5..88b3c0953 100644
--- a/nsock/src/nsock_iod.c
+++ b/nsock/src/nsock_iod.c
@@ -170,7 +170,7 @@ int socket_count_zero(msiod *iod, mspool *ms);
  * notification to each event), NSOCK_PENDING_SILENT (do not send notification
  * to the killed events), or NSOCK_PENDING_ERROR (print an error message and
  * quit the program) */
-void nsi_delete(nsock_iod nsockiod, int pending_response) {
+void nsi_delete(nsock_iod nsockiod, enum nsock_del_mode pending_response) {
   msiod *nsi = (msiod *)nsockiod;
   gh_lnode_t *evlist_ar[3];
   gh_list_t *corresp_list[3];