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