xmake-docs/docs/api/scripts/builtin-modules/signal.md

signal

2.9.1 adds a new signal registration interface. We can register signal processing functions such as SIGINT in the Lua layer to customize the response logic.

signal.register

• Register signal handler

Function Prototype

::: tip API

signal.register(signo: <number>, handler: <function>)

:::

Parameter Description

Parameter	Description
signo	Signal number (e.g., signal.SIGINT)
handler	Signal handler function

Usage

Currently, it only supports SIGINT signal processing, and it also supports mainstream platforms such as windows.

import("core.base.signal")

function main()
     signal.register(signal.SIGINT, function (signo)
         print("signal.SIGINT(%d)", signo)
     end)
     io.read()
end

This is useful when some sub-processes internally shield SIGINT, causing them to freeze and not exit. Even if the user presses Ctrl+C to exit the xmake process, it does not exit. We can force it out in this way.

import("core.base.process")
import("core.base.signal")

function main()
     local proc
     signal.register(signal.SIGINT, function (signo)
         print("sigint")
         if proc then
             proc:kill()
         end
     end)
     proc = process.open("./trap.sh")
     if proc then
         proc:wait()
         proc:close()
     end
end

For the background of this issue, please refer to: #4889

signal.ignore

• Ignore a signal

Function Prototype

::: tip API

signal.ignore(signo: <number>)

:::

Parameter Description

Parameter	Description
signo	Signal number (e.g., signal.SIGINT)

Usage

We can also ignore the processing of blocking a certain signal through the signal.ignore interface.

signal.ignore(signal.SIGINT)

signal.reset

• Reset a signal

Function Prototype

::: tip API

signal.reset(signo: <number>)

:::

Parameter Description

Parameter	Description
signo	Signal number (e.g., signal.SIGINT)

Usage

We can also clear the processing function of a certain signal and fall back to the default processing logic.

signal.reset(signal.SIGINT)