如何访问 C 函数中的 N 个参数并将相同的 N 传递给下一个？

Question

例如，这是我的 C ( & Objective-C ) 方法，如下所示。

void ALERT(NSString *title, NSString *message,NSString *canceBtnTitle,id delegate,NSString *otherButtonTitles, ... )
{
    // HERE I CAN ACCESS ALL THOSE ARGUMENTS
    // BUT I AM NOT SURE How to access additional arguments, supplied using ... ?

UIAlertView *alertView=[[UIAlertView alloc] initWithTitle:title 
                                                  message:message 
                                                 delegate:delegate 
                                        cancelButtonTitle:canceBtnTitle 
                                        otherButtonTitles:// how to pass those params here?];
}

如您所见，我还必须在UIAlertView 的init 方法中传递这些参数。我不确定如何将这些参数发送到otherButtonTitles。我可以通过以下方式调用这个方法。

ALERT(@"My Alert Title",@"Alert Subtitle",@"YES",viewCtr,@"No",@"May Be",@"Cancel",nil);

ALERT(@"Alert Title",@"Alert Subtitle",@"OK",viewCtr,@"Cancel",nil);

ALERT(@"Alert Title",@"Alert Subtitle",@"OK",viewCtr,nil);

ALERT(@"Alert Title",@"Alert Subtitle",@"OK",viewCtr,@"Option1",@"Option2",nil);

Answer 1

听起来你需要了解 va_arg（以及 va_list、va_start、va_end）。

Here's a tutorial on the subject.

另外，a fine Apple tech note entitled "How can I write a method that takes a variable number of arguments, like NSString's +stringWithFormat:?"

编辑添加：

听起来你想做va_copy。

啊，here is a related question。

Answer 2

嗯！我已经通过Wiki link

我也从Michael' Answer in this post那里学到了一些东西。

我想出了以下解决方案。

void ALERT(NSString *title, NSString *message,NSString *canceBtnTitle,id delegate,NSString *otherButtonTitles, ... )
{
    UIAlertView *alertView=[[UIAlertView alloc] initWithTitle:title 
                                                      message:message 
                                                     delegate:delegate 
                                            cancelButtonTitle:canceBtnTitle 
                                            otherButtonTitles:nil
                            ];

    va_list args;
    va_start(args, otherButtonTitles);
    NSString *obj;
    for (obj = otherButtonTitles; obj != nil; obj = va_arg(args, NSString*))
        [alertView addButtonWithTitle:obj];
    va_end(args);

    [alertView show];
}