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 type and 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.