handleFailureInFunction:file:lineNumber:description:Enterprise Objects Framework Release 1.0 Copyright ©1994 by NeXT Computer, Inc. All Rights Reserved.
| NSAssertionHandler |
| Inherits From: | NSObject | |
| Declared In: | foundation/NSException.h |
| Class Description |
| Assertion failures offer a convenient way to check for assertions. The NSAssertionHandler class manages assertion failures. Each thread has its own assertion-handler object, which usually work in coordination with a group of assertion macros. These macros 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.
The assertion macros come in two sorts, some for Objective-C methods and others for C functions. Two methods of NSAssertionHandler mirror this division; handleFailureInMethod:object:file:lineNumber:description: is used for assertion failures occurring within methods, while handleFailureInFunction:file:lineNumber:description handles assertion failures occurring in C functions. Both methods begin by logging an error message with NSLog(); the only difference in the message is method selector and object (handleFailureInMethod:...), and function name (handleFailureInFunction:...). Then both methods raise an exception of NSInternalInconsistencyException. Usually for assertions, you need only use the assertion macros NSAssert(), NSCAssert(), and other related macros, which incorporate the appropriate NSAssertionHandler methods. |
| Instance Variables |
| None declared in this class. |
| Method Types |
| Getting the thread's handler | + currentHandler | |
| Handling assertion failures | handleFailureInFunction:file:lineNumber:description: |
| handleFailureInMethod:object:file: |
| lineNumber:description: |
| Class Methods |
| currentHandler |
| + (NSAssertionHandler *)currentHandler |
| Returns the assertion handler for the current thread. |
| Instance Methods |
| handleFailureInFunction:file:lineNumber:description |
| (void)handleFailureInFunction:(NSString *)functionName |
| file:(NSString *)fileName lineNumber:(int)line description:(NSString *)formattedString, ... |
| This method logs an error message that includes the function, file, and line number and then raises an exception.
handleFailureInMethod:object:file:lineNumber:description |
| (void)handleFailureInMethod:(SEL)methodSelector |
| object:anObject file:(NSString *)fileName lineNumber:(int)line description:(NSString *)formattedString, ... |
| This method logs an error message that includes the class, method, file, and line number and then raises an exception. |