如何在Swift中使用CVaListPointer参数调用方法

Question

我该如何调用以下方法？该方法属于打印日志的类.

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

我想要实现的目标在Objective-C中看起来像这样:

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

有任何想法吗？

Answer 1

CVaListPointer是Swift等效的C va_list类型,可以[CVarArgType]使用数组创建withVaList().

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,替换CVarArgType为CVarArg.