Cancelling events: CancelEvent() & WasEventCanceled()

Sometimes a handler needs to veto an engine action or report that an event was rejected. CancelEvent() sets that signal, but it does not stop other handlers from running. WasEventCanceled() or Lua's TriggerEvent return value lets the code that triggered a local event inspect the result.

You'll learn: What CancelEvent() flags, why other handlers still run, how the caller checks cancellation, and the playerConnecting rejection pattern
Time: ~12 minutes
Prereqs: TriggerEvent and TriggerServerEvent / TriggerClientEvent
Outcome: You can cancel an event from a handler, detect cancellation downstream, and pick the right tool between cancel, return, and defer

BEFORE YOU START

Build it

Make the resource folder

The server has one folder for this lesson.

Inside your server's resources folder, create this folder:

code

resources/qu_cancelling_events

Create the files

Every file named in the manifest exists.

Create this exact file layout:

code

resources/qu_cancelling_events/
fxmanifest.lua
server.lua

Write fxmanifest.lua

FiveM knows which files to load.

Open fxmanifest.lua and paste this:

code

fx_version 'cerulean'
game 'gta5'

server_script 'server.lua'

Older tutorials add a lua54 'yes' line here. As of June 2025 that setting is deprecated and ignored: Lua 5.4 is now the only Lua runtime, so you leave it out.

Write the lesson code

The topic is now represented by runnable code.

Open server.lua and paste this. Two handlers listen for the same event, and a command fires it so you can watch the chain run:

code

AddEventHandler('qu_cancelling_events:check', function(name)
print('[qu_cancelling_events] first handler checked ' .. name)
if name == 'blocked' then
    CancelEvent()
    print('[qu_cancelling_events] event cancelled')
end
end)

AddEventHandler('qu_cancelling_events:check', function(name)
print('[qu_cancelling_events] second handler still ran for ' .. name)
end)

RegisterCommand('canceltest', function(_, args)
local name = args[1] or 'allowed'
print('[qu_cancelling_events] --- firing check for ' .. name .. ' ---')
TriggerEvent('qu_cancelling_events:check', name)
print('[qu_cancelling_events] caller saw cancelled = ' .. tostring(WasEventCanceled()))
end, true)
-- The final `true` is the "restricted" flag: it locks this command behind the
-- command.canceltest ACE permission. The server console (txAdmin Live Console
-- or the FXServer window) always has permission, so run `canceltest` THERE,
-- not from in-game chat, where a normal player would be silently denied.

Start and test it

The expected proof appears in the server console.

Open server.cfg and add this line:

code

ensure qu_cancelling_events

Save, then type this into the server console (the txAdmin Live Console, or the FXServer.exe window if you launched it directly):

code

restart qu_cancelling_events

Run the blocked case first:

code

canceltest blocked

Then run the allowed case:

code

canceltest open

The two handler lines may appear in a different order. The official contract is that cancellation does not prevent other handlers from running; do not depend on registration order. The caller's final cancellation result is the assertion that matters.

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