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C++:Nullptr

lastmod 2015-08-26created 2015-04-023 edits

NULL define

NULL as defined in GCC's stddef.h is as follows. 

/* A null pointer constant.  */
#if defined (_STDDEF_H) || defined (__need_NULL)
#undef NULL     /* in case <stdio.h> has defined it. */
#ifdef __GNUG__
#define NULL __null
#else   /* G++ */
#ifndef __cplusplus
#define NULL ((void *)0)
#else   /* C++ */
#define NULL 0
#endif  /* C++ */
#endif  /* G++ */
#endif  /* NULL not defined and <stddef.h> or need NULL.  */
#undef  __need_NULL

Or it can be used simply as follows. 

#ifndef NULL
#if defined(__cplusplus)
#define NULL 0
#else
#define NULL ((void*)0)
#endif
#endif

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