////  Singleton.h//  singleton////  Created by leondun on 11-4-20.//  Copyright 2011 leondun. All rights reserved.// #import 
     
        @interface Singleton : NSObject { } +(Singleton *)getInstance; @end
     

#import "Singleton.h" static Singleton * instance = nil; @interface Singleton(privateMethods) -(void)realRelease; @end  @implementation Singleton //获取单例+(Singleton *)getInstance{    @synchronized(self) {        if (instance == nil) {            [[self alloc] init];            }    }    return instance;} //唯一一次alloc单例，之后均返回nil+ (id)allocWithZone:(NSZone *)zone{    @synchronized(self) {        if (instance == nil) {            instance = [super allocWithZone:zone];            return instance;        }    }    return nil;} //copy返回单例本身- (id)copyWithZone:(NSZone *)zone{    return self;} //retain返回单例本身- (id)retain{    return self;} //引用计数总是为1- (unsigned)retainCount{    return 1;} //release不做任何处理- (void)release{   } //autorelease返回单例本身- (id)autorelease{    return self;} //真release私有接口-(void)realRelease{      [super release];} //-(void)dealloc{      //⋯⋯      printf("举例:在此处做一些单例结束时的收尾处理/n");       [super dealloc];} @end //程序结束时析构静态c++类对象garbo，//在Garbo类的析构函数中释放instancestruct Garbo{      ~Garbo(){[instance realRelease];}};static Garbo garbo;