KWNull.m 373 B

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  1. //
  2. // Licensed under the terms in License.txt
  3. //
  4. // Copyright 2010 Allen Ding. All rights reserved.
  5. //
  6. #import "KWNull.h"
  7. @implementation KWNull
  8. #pragma mark - Initializing
  9. + (id)null {
  10. static KWNull *sharedNull = nil;
  11. static dispatch_once_t onceToken;
  12. dispatch_once(&onceToken, ^{
  13. sharedNull = [self new];
  14. });
  15. return sharedNull;
  16. }
  17. @end