On: Conflating pointers with arrays: C's biggest mistake? (2009)

[ric129]

There's malloc_usable_size[1], assuming you mean asking the memory allocator what the array size is. But chances are that wouldn't work correctly, because what the amount of memory a malloc calls gives you and the amount you requested are often not the same. Modern memory allocators round up the request size to the nearest "size class".

[1]: http://man7.org/linux/man-pages/man3/malloc_usable_size.3.ht...