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Re: Mysterious crash in CFSTR()


On 2007 Mar 09, at 14:38, Dan Wright wrote:

Is InitCoreMidiDriver called more than once? Any chance MIDIClientCreate is releasing its first parameter? CFSTR only allocates a string the first time it is called, so you must either (a) never CFRelease a CFSTR string, or (b) remember to CFRetain it first.


Since Xcode 2.3, CFRetain() and CFRelease() have no effect on strings created via CFSTR().

Simple test:
Create a CFString via CFSTR().
Get its retain count.  The value is 0x10000000 I believe.
Retain it.
Check the retain count again.  No change.
Release it.
Check the retain count again.  No change.

BTW, this is a "magic number."  I did a test where I took a standard CFString, and kept retaining it until it hit the above number.  At that point CFRetain() and CFRelease() no longer had any effect.  On the other hand, I doubt many applications are going to need retain a string 2.7 billion times. :-D

Adin Hunter Baber

"Theory and practice are the same in theory, but different in practice."

 

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References: 
 >Mysterious crash in CFSTR() (From: Anthony Kozar <email@hidden>)
 >Re: Mysterious crash in CFSTR() (From: Dan Wright <email@hidden>)



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