From 19b03965fe70ceb1c4b4a29c2f0e0ef2330763d1 Mon Sep 17 00:00:00 2001
From: Micael Karlberg <bmk@erlang.org>
Date: Thu, 26 Oct 2023 09:54:58 +0200
Subject: [PATCH] [kernel|esock] Changed select and completion tag types

Make the select and completion tag types more expressive.

OTP-18818
---
 lib/kernel/doc/src/socket.xml |  5 +++--
 lib/kernel/src/socket.erl     | 17 +++++++++++++++--
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/lib/kernel/doc/src/socket.xml b/lib/kernel/doc/src/socket.xml
index 9aabdfce2c09..6dc84a2adb72 100644
--- a/lib/kernel/doc/src/socket.xml
+++ b/lib/kernel/doc/src/socket.xml
@@ -239,7 +239,7 @@
       <name name="select_tag"/>
       <desc>
 	<p>
-          A tag that describes the (select) operation,
+          A tag that describes the (select) operation (= function name),
           contained in the returned
           <seetype marker="#select_info"><c>select_info()</c></seetype>.
         </p>
@@ -272,7 +272,8 @@
       <name name="completion_tag"/>
       <desc>
 	<p>
-          A tag that describes the ongoing (completion) operation,
+	  A tag that describes the ongoing (completion) operation
+	  (= function name),
           contained in the returned
           <seetype marker="#completion_info"><c>completion_info()</c></seetype>.
         </p>
diff --git a/lib/kernel/src/socket.erl b/lib/kernel/src/socket.erl
index 16defc349146..68e79e599c34 100644
--- a/lib/kernel/src/socket.erl
+++ b/lib/kernel/src/socket.erl
@@ -793,8 +793,21 @@
 %% Interface term formats
 %%
 
--opaque select_tag()     :: atom() | {atom(), ContData :: term()}.
--opaque completion_tag() :: atom(). % | {atom(), ContData :: term()}.
+-define(ASYNCH_DATA_TAG, (recv | recvfrom | recvmsg |
+                          send | sendto | sendmsg)).
+-define(ASYNCH_TAG,      ((accept | connect) | ?ASYNCH_DATA_TAG)).
+
+%% -type asynch_data_tag() :: send | sendto | sendmsg |
+%%                            recv | recvfrom | recvmsg |
+%%                            sendfile.
+%% -type asynch_tag()      :: connect | accept |
+%%                            asynch_data_tag().
+%% -type select_tag()      :: asynch_tag() |
+%%                            {asynch_data_tag(), ContData :: term()}.
+%% -type completion_tag()  :: asynch_tag().
+-type select_tag()      :: ?ASYNCH_TAG | sendfile | 
+                           {?ASYNCH_DATA_TAG | sendfile, ContData :: term()}.
+-type completion_tag()  :: ?ASYNCH_TAG.
 
 -type select_handle() :: reference().
 -type completion_handle() :: reference().