NSAssertionHandler

Inherits From:
NSObject

Conforms To:
NSObject (NSObject)

Declared In:
Foundation/NSException.h

Class Description

You use an assortment of macros to evaluate a condition-these macros serve as a front end to NSAssertionHandler. These macros fall into two categories: those you use in Objective-C methods, and those you use in C functions. For example, NSAssert() is for use within methods and NSCAssert() is for use within functions. Each macro has two arguments: the condition, an expression that evaluates to true or false, and the NSString describing the failure. Other macros are available if more arguments are needed for a printf()-style description. For example, NSAssert1() is used within methods if an additional argument is needed as in:

NSAssert1((0 <= component) && (component <= 255),
    @"Value %i out of range!", component);

For more details on these macros see NSAssert().

You create assertions only using the above macros-you rarely need to invoke NSAssertionHandler methods directly. The macros for use inside methods and functions will send handleFailureInMethod:... and handleFailureInFunction:... to the current assertion handler respectively. The assertion handler for the current thread is obtained using the currentHandler class method.

Assertions are not compiled into code if the preprocessor macro NS_BLOCK_ASSERTIONS is defined.

Getting the thread's handler

+ currentHandler

Handling assertion failures

- handleFailureInFunction:file:lineNumber:description:

- handleFailureInMethod:object:file:lineNumber:description:

Class Methods

currentHandler

Returns an NSAssertionHandler for the current thread.

Instance Methods

handleFailureInFunction:file:lineNumber:description:

Logs an error message (using NSLog()) that includes the name of the function functionName, the name of the file fileName, and the line number line. Raises NSInternalInconsistencyException.

handleFailureInMethod:object:file:lineNumber:description:

Logs an error message (using NSLog()) that includes the selector, object's class name, the name of the file fileName, and the line number line. Raises NSInternalInconsistencyException.