Re: try/catch/throw/finally example?

FROM : Todd Yandell
DATE : Fri Aug 25 21:06:52 2006

On Aug 25, 2006, at 12:38 PM, Roland Silver wrote:

> Can someone suggest a tutorial or example of the use of @try, 
> @catch, @throw, @finally, in Objective-C, other than the Apple 
> document "Exception Handling and Thread Synchronization"?


NSString *stringOne = @"One";
NSString *stringTwo = @"Two";

@try {
    [stringOne appendString:stringTwo];    
} @catch (id theException) {
    NSLog(@"%@ doesn't respond to appendString:!", [stringOne class]);
} @finally {
    NSLog(@"This always happens.");
}

@throw [NSException exceptionWithName:@"Test"
    reason:@"Testing the @throw directive." userInfo:nil];

In the "@catch" block, "theException" will point to an NSException 
that describes the exception that was caught. The "@finally" block 
will always be executed, whether an exception was thrown or not. 
Normally you would use "@finally" to clean up any objects you created 
in the try "@try" block.

The "@throw" directive does the same thing as "[myException throw]".

You also need to enable these options in your build settings. In 
Xcode, check the "Enable Objective-C Exceptions" box in your target's 
build settings. With GCC, you need to use the "-fobjc-exceptions" flag.

Todd