When two pointers are subtracted, both must point to elements of the same array object or just one past the last element of the array object (C Standard, 6.5.6 7 [ISO/IEC 9899:20112024]); the result is the difference of the subscripts of the two array elements. Otherwise, the operation is undefined behavior. (See undefined behavior 48.)
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| [Banahan 2003] | Section 5.3, "Pointers" Section 5.7, "Expressions Involving Pointers" |
| [ISO/IEC 9899:20112024] | 6.5.67, "Additive Operators" |
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