Comment by uecker
3 months ago
C has arrays with more than one dimension. (but no direct support for strides). Of course, it is just the same thing as arrays of arrays.
3 months ago
C has arrays with more than one dimension. (but no direct support for strides). Of course, it is just the same thing as arrays of arrays.
Are C multidimensional arrays guaranteed to be contiguous in memory? In practice they are, but can one iterate through them just by incrementing a pointer which points to the first element without UB?
Yes. All arrays in C are contiguous. Multidimensional arrays are just arrays of arrays, and are therefore also contiguous.
Source: https://stackoverflow.com/questions/36647286/are-c-multidime...
Yes, but is one allowed to move a pointer inside it as they see fit? On a one-dimensional array, one can iterate through it starting with a pointer pointing to the first element and ending with a pointer pointing one position past the last element (which the user is not allowed to dereference). For multidimensional arrays, the element type is an array too (with a smaller rank than the original one), so one could perform that type of iteration with a pointer to an array. My question is whether a pointer to the underlying scalar type can freely move inside the multidimensional array without UB, since it may have to actually leave the array it was originally part of. If that's not allowed, how could one build slices and other view types?
4 replies →