error handling - ios checking for an empty object -


i have error getting passed reference code found online. error comes empty object meaning there no error.

if check error.code bad access because object empty.

if check error == nil false because error empty object.

how can use logic find error exists, empty?

errors of type nserror or subclass of it. passed references in methods declared way:

-(void)dosomestuff:(nserror **)error;

so, when call method requires pass reference nserror call way:

nserror *error = nil; [self dosomestuff:&error];

when method finished work check if error object has filled something:

if(error) {    //do stuff if there error.    //to see human readable description can:    nslog(@"the error was: %@", [error localizeddescription]);    //to see error code do:    nslog(@"the error code: %d", error.code); } else //there no error proceed normal {   //do other stuff - no error }

p.s. if no error , method not behave expected there wrong implementation method. if it's open source stuff, coding mistakes can appear, can take @ method does, debug , fix if wrong...


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