我通过终端加载了一项服务作为 launchctl load /System/Library/LaunchAgent/com.example.my.plist
现在，我需要以编程方式检测服务是否正在运行并启动服务。 http://www.opensource.apple.com/source/launchd/launchd-328/launchd/src/launch.h 上面是Apple提供的launch.h api的链接，有助于实现这一目标。
任何人都可以帮我处理它的文档吗？或者，帮助我如何使用 api 检查服务的状态并启动它。
谢谢。
此 API 的大部分内容现已弃用（macOS 10.14 SDK）：
/*!
* @header
* These interfaces were only ever documented for the purpose of allowing a
* launchd job to obtain file descriptors associated with the sockets it
* advertised in its launchd.plist(5). That functionality is now available in a
* much more straightforward fashion through the {@link launch_activate_socket}
* API.
*
* There are currently no replacements for other uses of the {@link launch_msg}
* API, including submitting, removing, starting, stopping and listing jobs.
*/
该解决方案似乎使用launchctl（man launchctl或此处的在线内容：https ://ss64.com/osx/launchctl.html ）。可能是这样launchctl list | grep <agent label>的。