c - 两个大于 INT_MAX 的 int 指针的差值

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两个 int* 有可能存在差异吗？指向同一数组元素的指针大于 INT_MAX ？

如果是这样，我如何访问这样一个数组中超出 INT_MAX 的元素？

Answer 1

Is is possible that the difference of two int* pointers on the elements of the same array is greater than INT_MAX?

是的，这是可能的。数组可以大于 INT_MAX元素。如此大的数组很少使用。

C提供ptrdiff_t作为指针减法的整数类型。

int *pointer_a;
int *pointer_b;
...
// pointer_a, pointer_b point to elements in the same array object.
ptrdiff_t diff = pointer_a - pointer_b;

// Use `%td` to print a `ptrdiff_t`.
printf("diff %td\n", diff);

When two pointers are subtracted, both shall point to elements of the same array object, or one past the last element of the array object; the result is the difference of the subscripts of the two array elements. The size of the result is implementation-defined, and its type (a signed integer type) is ptrdiff_t defined in the <stddef.h> ... C11dr §6.5.6 9

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how could I access the elements of such an array that are beyond INT_MAX?

对int之外的元素进行索引范围，使用指定的工作类型。

size_t是一些指定为足够宽以索引所有数组的无符号类型。

// some big array, maybe in global memory.
int big[10000000000];

....
size_t index = foo();
printf("big[%zu] = %d\n", index, big[index]);