UIModalTransitionStyleFlipHorizontal animation duration?

What is the default value of (NSTimeInterval)duration for UIM开发者_JS百科odalTransitionStyleFlipHorizontal, which is related to -[UIViewController presentModalViewController:animated:]?

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If you are asking what the default value of the duration is on an animation when you do not explicitly set it, the answer is provided in the framework headers:

 * If the `duration' property of the animation is zero or negative it
 * is given the default duration, either the value of the
 * `animationDuration' transaction property or .25 seconds otherwise.

So, since you can't set the value on the method call, it should take a quarter second to execute the animation.