Iphone 将间接指针强制转换为Objective-C指针

我有以下代码：

 OSStatus status = SecItemCopyMatching((__bridge CFDictionaryRef)attrDictionary, (CFTypeRef *)&value);

这会导致以下错误：

Implicit conversion of an indirect pointer to an Objective-C pointer to 'CFTypeRef *' (aka 'const void **') is disallowed with ARC

你知道怎么解决这个问题吗？我曾尝试将

CFTypeRef*

更改为

id*

，但没有成功

以下是完整的方法：

+ (NSData *)keychainValueForKey:(NSString *)key {
  if (key == nil) {
    return nil;
  }

  NSMutableDictionary *attrDictionary = [self attributesDictionaryForKey:key];

  // Only want one match
  [attrDictionary setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];

  // Only one value being searched only need a bool to tell us if it was successful
  [attrDictionary setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData];

  NSData *value = nil;
  OSStatus status = SecItemCopyMatching((CFDictionaryRef)attrDictionary, (CFTypeRef *)&value);
  if (status != errSecSuccess) {
    DLog(@"KeychainUtils keychainValueForKey: - Error finding keychain value for key. Status code = %d", status);
  }
  return [value autorelease];
}

---

您可以将其强制转换为

void*

：

OSStatus status = SecItemCopyMatching((__bridge CFDictionaryRef)attrDictionary,
    (void *)&value);

如果您使用的是Objective-C++，则可能需要将其强制转换两次：

OSStatus status = SecItemCopyMatching((__bridge CFDictionaryRef)attrDictionary,
    (CFTypeRef *)(void *)&value);

也可以使用临时变量：

CFTypeRef cfValue = NULL;
OSStatus status = SecItemCopyMatching((__bridge CFDictionaryRef)attrDictionary, &cfValue);
NSData *value = (__bridge id)cfValue;