Facebook iOS SDK和iOS6

我目前正在尝试在其3.14.1版本中使用Facebook SDK官方pod(也试过3.9,同样的结果),但我偶然发现了一个问题.

这是我的代码:

self->_session = [[FBSession alloc] initWithAppID:[[self class] facebookAppId]
                                      permissions:self.mandatoryPermissions
                                  urlSchemeSuffix:nil
                               tokenCacheStrategy:[FBSessionTokenCachingStrategy defaultInstance]];


[self->_session openWithBehavior:FBSessionLoginBehaviorWithFallbackToWebView
               completionHandler:^(FBSession *session,
                                       FBSessionState state,
                                       NSError *error)
{
    [self sessionStateChanged:session
                        state:state
                        error:error];
}];

这非常受到facebook提供的代码示例的启发:https://developers.facebook.com/docs/facebook-login/ios/v2.0#步骤1b:使用自定义类打开会话

这是问题:

dyld: lazy symbol binding failed: Symbol not found: _OSAtomicDecrement32
  Referenced from: /var/mobile/Applications/01DD5CE2-39A9-40AE-A8FC-170F7387D434/Dubb.app/Dubb
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: _OSAtomicDecrement32
  Referenced from: /var/mobile/Applications/01DD5CE2-39A9-40AE-A8FC-170F7387D434/Dubb.app/Dubb
  Expected in: /usr/lib/libSystem.B.dylib

通过查看他们的SDK代码,我无法看到OSAtomicDecrement32它不存在的后备,并且它实际上存在于iOS 7.1的开始.

有什么建议？

谢谢