In c language. What happens when we subtract Null pointer from char *
int i = (char *)a - (char *)0;
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2I think the result is undefined. – Tom Karzes Oct 18 '20 at 13:09
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What is `a` defined as? – DaV Oct 18 '20 at 13:09
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Does this answer your question? [Can we subtract NULL pointers?](https://stackoverflow.com/questions/55747642/can-we-subtract-null-pointers) – phuclv Oct 18 '20 at 13:58
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@phuclv No. But I found the answer https://stackoverflow.com/a/39836849/5144634 – iobloxx Oct 18 '20 at 14:15
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Pointer difference is defined only for two pointers that both point into or just past the end of the same array (where a pointer to a non-array object is considered as if it were a pointer to a one-element array). By definition, a null pointer does not point to any object, therefore no pointer difference involving a null pointer has defined behavior. Not even the difference between two null pointers.
John Bollinger
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