OSX 监听系统网络设置

由于日常开发的需求，我们需要监听OSX一些系统设置的变化，达到软件程序设置的同步，这时我们可以通过以下函数监听系统设置的改变：

#include <SystemConfiguration/SystemConfiguration.h>

//------------------------------------------------------------------
    SCDynamicStoreRef dynStore;
    SCDynamicStoreContext context = {0, this, NULL, NULL, NULL};
    dynStore = SCDynamicStoreCreate(kCFAllocatorDefault,
                                    CFBundleGetIdentifier(CFBundleGetMainBundle()),
                                    SystemProxyChangeCallBack,//自定义回调函数，备注【1】
                                    &context);
    const CFStringRef keys[3] = {CFSTR("State:/Network/Global/Proxies")};//获取系统代理设置，备注【2】
    CFArrayRef watchedKeys = CFArrayCreate(kCFAllocatorDefault,
                                           (const void **)keys,
                                           1,
                                           &kCFTypeArrayCallBacks);
    if (SCDynamicStoreSetNotificationKeys(dynStore, NULL, watchedKeys))
    {
        CFRelease(watchedKeys);
        CFRunLoopSourceRef rlSrc = SCDynamicStoreCreateRunLoopSource(kCFAllocatorDefault, dynStore, 0);
        CFRunLoopAddSource(CFRunLoopGetCurrent(), rlSrc, kCFRunLoopDefaultMode);
        CFRelease(rlSrc);
    }
    else
    {
        CFRelease(watchedKeys);
        CFRelease(dynStore);
        dynStore = NULL;
    }
//------------------------------------------------------------------
   CFRunLoopRun(); //在程序中需要调用该函数监听效果

//================================================

备注【1】，当系统设置有所改变时，会触发该回调函数，可根据具体需要做相关的操作处理

void SystemProxyChangeCallBack(SCDynamicStoreRef store, CFArrayRef changedKeys,void *info)
{
}

备注【2】，这里demo程序为监听网络代理改变属性的设置，其他属性值可参考：

https://developer.apple.com/library/mac/documentation/Networking/Conceptual/SystemConfigFrameworks/SC_UnderstandSchema/SC_UnderstandSchema.html