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POHow to convert from char* to id* with ARC enabled
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copied!<p>I'm trying to construct "fake" variable arguments list, using the technique described <a href="http://cocoawithlove.com/2009/05/variable-argument-lists-in-cocoa.html" rel="nofollow">here</a>, but for ARC-enabled project and I can't figure out how to get rid of the error I'm getting.</p> <p>Here's the code in question:</p> <pre><code>NSMutableArray* argumentsArray = [NSMutableArray array]; // ... Here I fill argumentsArray with some elements // And then, I want to construct a "fake" variable argument list char* fakeArgList = (char*) malloc( sizeof(NSString*) * [argumentsArray count]); [argumentsArray getObjects: (id*) fakeArgList]; NSString* content = [[NSString alloc] initWithFormat: formatString arguments:fakeArgList]; </code></pre> <p>XCode complains on the <em>(id</em>) fakeArgList* casting, saying:</p> <blockquote> <p>Cast of non-Objective-C pointer type 'char *' to '_autoreleasing id *' is disallowed with ARC</p> </blockquote> <p>My initial theory was that I just need to add __unsafe_unretained to (id*) casting to tell ARC that I'm responsible for that block of memory and it shouldn't retain/release it, but that doesn't work and I can't figure out how to fix this problem.</p> <p><strong>Update:</strong> Here's the full function. It should take a printf-style format string and a variable list of field names inside the .plist and output a formatted string with data loaded from .plist. I.e., if I have a .plist file with fields "field1" = "foo" and "field2" = 3 and I call <code>[loadStringFromFixture: @"?param1=%@&param2=%d", @"field1", @field2]</code> then I should get string "?param1=foo&param2=3"</p> <pre><code>- (NSString*) loadStringFromFixture:(NSString*) format, ... { NSString* path = [[NSBundle mainBundle] bundlePath]; NSString* finalPath = [path stringByAppendingPathComponent:@"MockAPI-Fixtures.plist"]; NSDictionary* plistData = [NSDictionary dictionaryWithContentsOfFile:finalPath]; va_list argumentsList; va_start(argumentsList, format); NSString* nextArgument; NSMutableArray* argumentsArray = [NSMutableArray array]; while((nextArgument = va_arg(argumentsList, NSString*))) { [argumentsArray addObject: [plistData objectForKey:nextArgument]]; } NSRange myRange = NSMakeRange(0, [argumentsArray count]); id* fakeArgList = (__bridge id *)malloc(sizeof(NSString *) * [argumentsArray count]); [argumentsArray getObjects:fakeArgList range:myRange]; NSString * content = [[NSString alloc] initWithFormat:formatString arguments:(__bridge va_list)fakeArgList]; free(fakeArgList); return content; } </code></pre>

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