如何在Swift中使用CVaListPointer参数调用方法

问题描述

我应该如何调用以下方法?该方法属于打印日志的类.

How should I invoke the following method? The method belongs to a class that prints logs.

func log(format: String!, withParameters valist: CVaListPointer)

我要实现的目标在Objective-C中如下所示:

What I want to achieve, would look like this in Objective-C:

NSLog(@"Message %@ - %@", param1, param2);

有什么想法吗?

推荐答案

CVaListPointer是C va_list类型的Swift等效项可以使用withVaList()从[CVarArgType]数组创建.

CVaListPointer is the Swift equivalent of the C va_list typeand can be created from an [CVarArgType] array using withVaList().

示例:

func log(format: String!, withParameters valist: CVaListPointer) {
    NSLogv(format, valist)
}

let args: [CVarArgType] = [ "foo", 12, 34.56 ]
withVaList(args) { log("%@ %ld %f", withParameters: $0) }

输出:

2016-04-27 21:02:54.364 prog[6125:2476685] foo 12 34.560000

对于 Swift 3，将CVarArgType替换为CVarArg.

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