NSInvocationOperation with return value (BOOL)

hi i have these invocation operation:

NSInvocationOperation *operation = [[NSInvocationOperation alloc] 
             initWithTarget:ndParser selector:@开发者_开发知识库selector (parseUrl:)
             object:[NSString stringWithFormat:@"http://URL%@",var]];

my method:

- (BOOL) parseUrl:(NSString *)URL;

should throw back bool....

how can i catch this value?

regards

You can get the result like this:

BOOL result;
[[operation result] getValue:&result];

From the docs here.