Re: Help with detecting invalid object when in if() test....
Re: Help with detecting invalid object when in if() test....
- Subject: Re: Help with detecting invalid object when in if() test....
- From: "Alastair J.Houghton" <email@hidden>
- Date: Fri, 15 Aug 2003 17:56:31 +0100
On Friday, August 15, 2003, at 03:19 pm, Steven M.Palm wrote:
I know this sounds very basic, but I can't seem to get it right.
I have the following:
sig = [bEnd mySig];
And this doesn't always return a valid object... If I try to use the
name method on sig, [sig name], it will generate an exception if sig
is not a valid object, -[NSNull name]: selector not recognized.
Okay, I thought I would just put the code that acts on sig inside an
if statement...
if (sig) { blah }
The problem is that your -mySig method isn't returning a valid pointer
to an object. I'd check the function to make sure you're always
returning something, even if that something is "nil". Also, if you're
returning the value of a local variable, make sure you initialise the
variable (at least to "nil") before you return.
Objective C is just like C, and you would have had the exact same
problem there.
Kind regards,
Alastair.
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