Re: argument checks
Re: argument checks
- Subject: Re: argument checks
- From: Graham Cox <email@hidden>
- Date: Thu, 12 Jun 2008 16:51:38 +1000
NSNumber* myNum = nil;
/* stuff */
NSAssert( myNum != nil, @"some error message");
[myClass calc:myNum];
Messages to nil are safe - it will treat your number as having a value
of 0. Thus as long as you initialise it to nil, your code will run
without crashing though of course may give incorrect results. If you
don't initialise it to anything, it will almost certainly crash. The
compiler should be warning you about this - if not, make it do so.
G.
On 12 Jun 2008, at 3:50 pm, Ashley Perrien wrote:
Noob question: I'm putting together a small code library and I'm
trying to include some error checking in the methods; what I want to
protect against is the following:
NSNumber *myNum;
// Lots of code where I've forgotten to actually do anything with
myNum
results = [myClass someCalculationUsing: myNum];
myNum in this case is an object and does exist but it's not a valid,
usable argument. So in the implementation I'd like to have something
along the lines of:
if (myNum == nil)
NSLog(@"some error message");
but can't figure out what to check for that would get me into the
error message condition. Any suggestions?
Ashley Perrien
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