In C, practical 2-D arrays are built as array of pointer to "type" and that pointer array is NULL terminated. In this case, pointer to pointer to char. The "built-in" C 2D array is pretty much worthless in practical applications.

Actually, NULL termination is almost invariably a terrible idea. It wastes space, because you should know how long the array is. If you don't know how long the array is, then you can only safely access it sequentially; if you need random access, this means you have to calculate the length anyway, by scanning the whole thing looking for the NULL, before you can access it at all. This is an unnecessary complication when you could just use that extra word of memory to store the length of the array in the first place.

To be honest, storing as pointer-to-pointer is also often an unnecessary complication. It's very easy to mess up memory management when nesting pointers.

In reply to Re^2: Passing a bytestring from Perl to Inline::C as a 2d array by Porculus
in thread Passing a bytestring from Perl to Inline::C as a 2d array by maasha

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