参考https://www.jianshu.com/p/6b012ebc10fe
.h文件
```objective-c
#import
@interfaceCYWinLoseSound :NSObject
+ (instancetype) shareTsetSington;
@end
```objective-c
```objective-c
.m文件
#import "FTTsetSington.h"
@implementation FTTsetSington
static FTTsetSington*_instance =nil;
+ (instancetype) shareTsetSington{
// staticdispatch_once_tonceToken;不用手打，你直接打dispatch_once会直接生成staticdispatch_once_tonceToken这句
staticdispatch_once_tonceToken;
//dispatch_once这个函数可以使其参数内的block块只在全局执行一次从而达到目的
dispatch_once(&onceToken, ^{
_instance = [[self alloc] init];
});
return _instance;
}
@end
```objective-c
