C++, the steampunk language [LWN.net]

C++, the steampunk language

Posted Sep 14, 2009 16:17 UTC (Mon) by tjc (guest, #137)
In reply to: C++, the steampunk language by felixfix
Parent article: Writing kernel modules in Haskell

My experience with C++ is summed up by having replaced the simple malloc/free paradigm with THREE different ways to allocate : new/delete, new[]/delete[], and the original.

Since you bring it up, do you happen to know why C++ requires a separate form (new[] v. new) for allocating and deallocating arrays?

I'm aware that arrays are converted to pointers in parameter declarations and (most) expressions, but I don't think that's an issue here. There should be enough information in the symbol table to identify an object as an array and [de]allocate memory for it without resorting to a special form.

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C++, the steampunk language

Posted Sep 14, 2009 16:21 UTC (Mon) by avik (subscriber, #704) [Link]

delete[] needs to call the destructors of every element of the array, so it needs to know it is destroying an array.

C++, the steampunk language

Posted Sep 14, 2009 16:30 UTC (Mon) by nye (guest, #51576) [Link]

Note that there is a bit more to it than that, otherwise it would be okay to use delete on an array of POD types, which it isn't (see my other post). That's undoubtedly the root reason though.

C++, the steampunk language

Posted Sep 14, 2009 16:26 UTC (Mon) by nye (guest, #51576) [Link]

The first response to http://stackoverflow.com/questions/659270/why-is-there-a-... gives a reasonable answer.

C++, the steampunk language

Posted Sep 14, 2009 17:43 UTC (Mon) by tjc (guest, #137) [Link]

Thanks for the link. There is some other useful information on that page; see the post by Andrew Grant.

IIUC the size of an object could be stored in the symbol table, but that would only work with objects within lexical scope-- a dynamically allocated object returned from a library function would still be a problem, since there is no portable way to attach size information to an object in C.