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Re: Why is NULL used sometimes when documentation specifies nil?
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Re: Why is NULL used sometimes when documentation specifies nil?


  • Subject: Re: Why is NULL used sometimes when documentation specifies nil?
  • From: Roarke Lynch <email@hidden>
  • Date: Fri, 14 Jan 2005 22:01:25 -0500

What is the difference between nil and NULL?

Why does the Foundation Reference for NSScanner specify nil to skip search results, while the NSScanner example in "Strings" documentation uses NULL to omit results?
[snip
So why is NULL used sometimes when documentation specifies nil?

Well nil is used to imply no object in Cocoa Objective-C and NULL for traditional uses of NULL in C. In reality they are one in the same value so they can be used interchangeably.


The code example, in a perfect world, should be using nil since intoString is expecting an object.

-Shawn

Knowing that nil and NULL are essentially the same value, I was under the impression that syntactically nil refers to "no object" while NULL referrers to "a pointer to nothing", so in the the NSScanner method in question since the argument is of type NSString** not NSString* NULL is used because it is the second case.


Roarke Lynch
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  • Follow-Ups:
    • Re: Why is NULL used sometimes when documentation specifies nil?
      • From: Shawn Erickson <email@hidden>
References: 
 >Why is NULL used sometimes when documentation specifies nil? (From: Jeremy French <email@hidden>)
 >Re: Why is NULL used sometimes when documentation specifies nil? (From: Shawn Erickson <email@hidden>)

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