Condition of the for loop with defined arraylength(*array)

[Ducol]

Hi!

EDIT: this was an irrelevant post - the array size is specified in the program I am referring to, so no magic. I can't delete the post, so I am sorry if you have lost your time reading it.

Please, help me to understand how the size of the array is used in the following part of the program, which I have found on this forum.
We define the size of the array as

#define ARRAYLENGTH(x) (sizeof(x)/sizeof(*(x)))

Then in the program we get information from the file and put that into the array using the for loop. My question about the condition of the loop

j < ARRAYSIZE(*array)

: when the loop starts, the array is not yet populated, so the size is equal to sizeof(the whole array which is null at the first iteration of the loop)/sizeof(first member of the array)). Please, help me to understand how this condition works, and how to interpret it.

      for ( i = 0; fgets(buffer, sizeof buffer, file); ++i )
      {
         for ( j = 0, ptr = buffer; j < ARRAYLENGTH(*array); ++j, ++ptr )
         {
            array[i][j] = (int)strtol(ptr, &ptr, 10);
         }
      }

Thanks a lot!

[algorism]

You haven't told us what "array" is. It could be anything. And the fact that it's being dereferenced in the ARRAYLENGTH call is suspicious. That's not usually how that code is used.