NSParameterAssert

最新推荐文章于 2021-02-07 11:19:57 发布

最新推荐文章于 2021-02-07 11:19:57 发布 · 146 阅读

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本文介绍了Objective-C中的NSParameterAssert宏，用于验证方法参数的有效性。当参数条件为假时，会记录错误信息并抛出异常。文章还解释了断言处理机制及如何禁用断言。

NSParameterAssert

Validates the specified parameter.

NSParameterAssert(condition)

Discussion

Assertions evaluate a condition and, if the condition evaluates to false, call the assertion handler for the current thread, passing it a format string and a variable number of arguments. Each thread has its own assertion handler, which is an object of class NSAssertionHandler. When invoked, an assertion handler prints an error message that includes method and class names (or the function name). It then raises an NSInternalInconsistencyException exception.

This macro validates a parameter for an Objective-C method. Simply provide the parameter as the condition argument. The macro evaluates the parameter and, if it is false, it logs an error message that includes the parameter and then raises an exception.

Assertions are disabled if the preprocessor macro NS_BLOCK_ASSERTIONS is defined. All assertion macros return void.

Availability