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例如
func hello() -> Bool { var result = false httpRequestWithCompletionHandler({ is404 in result = is404 }) return result }
这个函数的返回值永远是 false，因为 closure 是异步执行的怎么在调用这个函数的时候，得到真正的返回值呢？注： result 必须定义在函数体内，不能定义在函数体外
小伙看你根骨奇佳，潜力无限，来学PHP伐。
var result_cb = function (result) { alert(result) }; function hello(cb) { httpRequestWithCompletionHandler(is404) { cb(is404); } } hello(result_cb);
Like this?
GO lang ? Asynchronously executed functions can only obtain values through callbacks, so the results cannot be obtained directly by returning bool from hello.
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
Like this?
GO lang ? Asynchronously executed functions can only obtain values through callbacks, so the results cannot be obtained directly by returning bool from hello.