IOS 单例模式（非ARC）

 singleton_h ：连接字符串和参数

// ## : 连接字符串和参数
#define singleton_h(name) + (instancetype)shared##name;

#define singleton_m(name) 
static id _instance; 
+ (id)allocWithZone:(struct _NSZone *)zone 
{ 
    static dispatch_once_t onceToken; 
    dispatch_once(&onceToken, ^{ 
        _instance = [super allocWithZone:zone]; 
    }); 
    return _instance; 
} 
 
+ (instancetype)shared##name 
{ 
    static dispatch_once_t onceToken; 
    dispatch_once(&onceToken, ^{ 
        _instance = [[self alloc] init]; 
    }); 
    return _instance; 
} 
 
- (oneway void)release 
{ 
 
} 
 
- (id)autorelease 
{ 
    return _instance; 
} 
 
- (id)retain 
{ 
    return _instance; 
} 
 
- (NSUInteger)retainCount 
{ 
    return 1; 
} 
 
+ (id)copyWithZone:(struct _NSZone *)zone 
{ 
    return _instance; 
}

调用单例模式  Singleton.h /.m

#import <Foundation/Foundation.h>
#import "Singleton.h"

@interface HMMainTool : NSObject
singleton_h(MainTool)
@end

#import "HMMainTool.h"

@implementation HMMainTool
singleton_m(MainTool)
@end

调用类

#import "HMViewController.h"
#import "HMAudioTool.h"
#import "HMNetTool.h"
#import "HMMainTool.h"

@interface HMViewController ()

@end

@implementation HMViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    HMAudioTool *audio1 = [[HMAudioTool alloc] init];
    HMAudioTool *audio2 = [HMAudioTool sharedAudioTool];
    NSLog(@"1111%p %p", audio1, audio2);
    
    HMNetTool *net1 = [[HMNetTool alloc] init];
    HMNetTool *net2 = [HMNetTool sharedNetTool];
    NSLog(@"2222%p %p", net1, net2);
    
    HMMainTool *main1 = [[HMMainTool alloc] init];
    HMMainTool *main2 = [HMMainTool sharedMainTool];
    NSLog(@"333%p %p", main1, main2);
}

@end