iphone memset issue

I defined a struct in my header file:

#import <UIKit/UIKit.h>    
typedef struct ORIGINAL_QUOTA_DATA_tag
{
    byte    exch;    开发者_运维技巧      
    byte    complex_stat;                   
    char    contract[8];    
    byte    status;         
    byte    type;        
}ORIGINAL_QUOTA_DATA;
@interface NetTestAppDelegate : NSObject <UIApplicationDelegate> {
    CFSocketRef _socket;
    CFDataRef address;
    ORIGINAL_QUOTA_DATA oQuota;
}
@property (nonatomic, retain) IBOutlet UIWindow *window;

in my .m file:

    static void TCPServerConnectCallBack(CFSocketRef socket, CFSocketCallBackType type, CFDataRef address, const void *data, void *info){
memset(&oQuota, 0, sizeof(oQuota));
}

but it gets worning:

You are referencing oQuota from C function (it's also static but that's not the problem). Your oQuota variable is only "in scope" inside Objective-C methods implementation for your NetTestAppDelegate:

void myCFunction()
{
    // oQuota cannot be referenced here.
}

@implementation NetTestAppDelegate
- (void)myObjectiveCMethod
{
   // oQuota is in scope, can reference it.
}
@end

But what you can do is pass the object to your callback:

static void TCPServerConnectCallBack(CFSocketRef socket, CFSocketCallBackType type, CFDataRef address, const void *data, void *info){
    memset(
      &((NetTestAppDelegate *)info)->oQuota,
      0,
      sizeof(((NetTestAppDelegate *)info)->oQuota)
    );
    // Not sure whether the sizeof works, try it.
}

In your CFSocketContext, you then need to set:

myCFSocketContext.info = self;