WowAce

An edit in SendCommMessage prevents the usage of a number for the "target" parameter.

When using a custom chat channel, the "target" parameter needs to be the channelID (a number) returned by GetChannelName("channel_name").

I made a change to my copy of  SendCommMessage to allow "target" to be a number and everything works with using custom chat channels created with the

 JoinTemporaryChannel() API call.

SendCommMessage is a wrapper around SendAddonMessage, I don't think you can send those to custom channels.

What kind of parameter would that be for type/distribution?

I verified, you can send to custom channels.  Also, I put in my issue that i changed "SendCommMessage" to allow target to be a number and it worked.  The number used is returned by:  GetChannelName("channel_name").

Example:

self.Prefix = 'MyPrefix"
self.ChannelName = 'MyChannel'
self.ChannelPassword = 'AbCd123'
local _, _ = JoinTemporaryChannel(self.ChannelName ,self.ChannelPassword)
self.ChannelID, _ = GetChannelName(self.ChannelName)
self:SendCommMessage(self.Prefix, Data, 'CHANNEL', self.ChannelID)

Hi.

I can confirm it. SendAddonMessage support use of custom channels. I've wrote following code for testing, shared it as addon with a guild member and it works.

local C = WrapTextInColorCode;
local frame = CreateFrame("frame");
local prefix,chan,pw,id = "CCT-Px","CustomChannelTest","CustomChannelTest",false;

frame:SetScript("OnEvent",function(self,event,...)
	if event=="PLAYER_LOGIN" then
		C_Timer.After(8,function()
			if (RegisterAddonMessagePrefix(prefix)~=nil) and (JoinTemporaryChannel(chan,pw)~=nil) then
				local chanId,chanName = GetChannelName(chan);
				if chanId then
					print(C("[Channel registered]","ffffee00"),"id="..C(chanId,"ff00ff00"));
					SendAddonMessage(prefix,"channel-testing","CHANNEL",chanId);
				end
			end
		end);
	elseif event=="CHAT_MSG_ADDON" and prefix==... then
		local _,msg,chType,toon,chLabel = ...;
		print(C("[AddOnMsg]","ffffee00"), "player="..C(toon,"ff00aaff"), "chan="..C(chLabel,"ffff7700"), "msg="..C(msg,"ff00ff00"));
	end
end);

frame:RegisterEvent("PLAYER_LOGIN");
frame:RegisterEvent("CHAT_MSG_ADDON");

Greetings Hizuro

I'm using ACE3 version: Ace3 Release - Revision r1166 (August 29th, 2017)
which I got using the Twitch (Curse) desktop app.

When I use a custom channel, I'm getting the following error:
--------------------
1x Census\Census-101.lua:3498: Usage: SendCommMessage(addon, "prefix", "text", "distribution"[, "target"[, "prio"[, callbackFn, callbackarg]]])
[C]: ?
Ace3\AceComm-3.0\AceComm-3.0-10.lua:91: in function `SendCommMessage'
--------------------

The error is caused by line 88 of AceComm-3.0.lua which is a part of a series of conditional statements with a NOT in front of it:
(target==nil or type(target)=="string") and

This throws an error if the "target", which is the channel number, is NOT of type "string".

Census - is the name of the addon that I wrote.