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Overview

@async marks a function as asynchronous. In GLua, this often means the function calls coroutine.yield and must run inside a coroutine. The annotation affects documentation and async-aware diagnostics. It does not change runtime behavior.

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Syntax

---@async

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Usage

---@async
---@param url string The URL to fetch
---@return string response The response body
function fetch(url)
    -- internally yields waiting for I/O
    local response = http.Fetch(url)
    coroutine.yield()
    return response
end

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What it does

  • Marks the function in hover documentation as async
  • Allows tools and linters to warn when an @async function is called outside a coroutine context (if that diagnostic is enabled)
  • Has no runtime effect

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Common GMod patterns

GLuaLS supports async-style code that uses coroutines and callbacks. GMod has no built-in await(), but many addons use helper wrappers for the same pattern. 
---@async
function PLUGIN:FetchPlayerData(steamId)
    local response
    http.Fetch("https://api.example.com/player/" .. steamId, function(body)
        response = body
    end)

    coroutine.yield() -- wait for the callback to set `response`
    return response
end