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  • what is NSParameterAssert?

    It is a simple way to test that a methods parameter is not nil or not 0. So basically, you use it to create a precondition, stating that some parameter must be set. If it is not set, the macro causes the application to abort and generates an error on that line. So:

    - (void)someMethod:(id)someObjectThatMustNotBeNil
    {
      // Make sure that someObjectThatMustNotBeNil is really not nil
      NSParameterAssert( someObjectThatMustNotBeNil );
      // Okay, now do things
    }

    Pre-conditions are a simple way to ensure that methods/API are being called correctly by the programmer. The idea is that if a programmer violates the precondition, the application terminates early--hopefully during debugging and basic testing.

    NSParameterAssert can be used to test that any expression evaluates to true, however, so you can use it like this as well:

    NSParameterAssert( index >=0);// ensure no negative index is supplied
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  • 原文地址:https://www.cnblogs.com/mumue/p/3067981.html
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