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    <h2>UPDATE</h2> <p>Core Foundation has a bug that makes <code>CFAllocatorSetDefault</code> useless.</p> <p>Specifically, if you study the implementation of <code>_CFRuntimeCreateInstance</code> in <a href="http://www.opensource.apple.com/source/CF/CF-744.18/CFRuntime.c" rel="nofollow"><code>CFRuntime.c</code></a>, you'll see that:</p> <ul> <li>If it's not using the system default allocator, it tries to retain the allocator.</li> <li>If it's been passed <code>NULL</code> as its <code>allocator</code> argument, it will try to retain that <code>NULL</code> instead of the current default allocator.</li> <li>The call to <code>CFRetain</code> will therefore crash.</li> </ul> <p>What it <strong>should</strong> do is retain the current default allocator when it's given <code>NULL</code> as its <code>allocator</code> argument.</p> <p>Since lots of functions in Apple's own libraries apparently pass <code>NULL</code> (or <code>kCFAllocatorDefault</code>, which is also a null pointer) to functions that create a Core Foundation object, you're bound to crash quickly if you change the default allocator at all.</p> <p>My test case: I created a new, single-view iPhone app. I added one line to <code>main</code>:</p> <pre><code>int main(int argc, char *argv[]) { CFAllocatorSetDefault(kCFAllocatorMalloc); @autoreleasepool { return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class])); } } </code></pre> <p>The app crashes during startup on the simulator and on my test device, in <code>CFRetain</code>, with <code>EXC_BREAKPOINT</code>, with a null pointer as the function argument.</p> <h2>ORIGINAL</h2> <p>You are passing a null pointer to <code>CFRetain</code>. If this has anything to do with your custom allocator, you need to post more details, like the full call stack when the exception occurs.</p> <p>In your disassembly listing, the instructions from <code>0x1c089b0</code> through <code>0x1c089bd</code> are the function prologue.</p> <p>At <code>0x1c089be</code>, the <code>movl 8(%ebp), %esi</code> instruction loads the first function argument from the stack into <code>%esi</code>.</p> <p>At <code>0x1c089c1</code>, the <code>testl %esi, %esi</code> instruction sets the processor flags based on the value of <code>%esi</code>. In particular, it sets the Z (zero) flag to 1 if <code>%esi</code> contains zero, and sets the Z flag to 0 if <code>%esi</code> contains anything else.</p> <p>At <code>0x1c089c3</code>, the <code>jne 0x1c089db</code> instruction jumps if the <code>ne</code> condition is true. The <code>ne</code> condition is true when the Z flag is 0 and false when the Z flag is 1. So this instruction jumps when <code>%esi</code> (the first argument) is non-zero, and falls through when <code>%esi</code> is zero.</p> <p>At <code>0x1c089c5</code>, the <code>int3</code> instruction raises a <code>SIGTRAP</code> signal with exception code <code>EXC_BREAKPOINT</code>. The <code>int3</code> instruction is normally stuffed into a program by the debugger when you set a breakpoint. In this case, it was hardcoded in the program at compile-time.</p> <p>Thus, you are getting this exception because you are passing a null pointer to <code>CFRetain</code>.</p> <p>You can also look at the source code of <code>CFRetain</code> if you like. It is in <a href="http://www.opensource.apple.com/source/CF/CF-744.18/CFRuntime.c" rel="nofollow"><code>CFRuntime.c</code></a>:</p> <pre><code>CFTypeRef CFRetain(CFTypeRef cf) { if (NULL == cf) { CRSetCrashLogMessage("*** CFRetain() called with NULL ***"); HALT; } if (cf) __CFGenericAssertIsCF(cf); return _CFRetain(cf, false); } </code></pre> <p>So the very first thing <code>CFRetain</code> does is test whether its argument is <code>NULL</code>. <code>CGSetCrashLogMessage</code> is a macro defined in <a href="http://www.opensource.apple.com/source/CF/CF-744.18/CoreFoundation_Prefix.h" rel="nofollow"><code>CoreFoundation_Prefix.h</code></a> that does nothing. <code>HALT</code> is a macro defined in <a href="http://www.opensource.apple.com/source/CF/CF-744.18/CFInternal.h" rel="nofollow"><code>CFInternal.h</code></a>:</p> <pre><code> #define HALT do {asm __volatile__("int3"); kill(getpid(), 9); } while (0) </code></pre> <p>As you can see, <code>HALT</code> has a hard-coded <code>int3</code> instruction. Then it calls <code>kill(getpid(), 9)</code>. This matches your disassembly listing.</p>
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    1. POAnyone use CFAllocatorSetDefault succesfully in an iPhone app?
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    1. POAnyone use CFAllocatorSetDefault succesfully in an iPhone app?
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    1. COHere's the partial stack when the exception occurred: ` frame #0: 0x01c169c6 CoreFoundation`CFRetain + 22 frame #1: 0x01c17917 CoreFoundation`_CFRuntimeCreateInstance + 391 frame #2: 0x01c202aa CoreFoundation`__CFArrayInit + 202 frame #3: 0x01c201d0 CoreFoundation`__CFArrayCreateMutable0 + 32 frame #4: 0x035c2e52 WebCore`WKViewAddSubview + 114 frame #5: 0x0356f316 WebCore`-[WAKView addSubview:] + 102` The native CFRetain is called and probably doesn't like something that my allocator created early on.
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    2. COAnyways, thanks a lot!
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    3. COI have updated my answer based on your stack trace.
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