Part I This C++ FAQ entry explained why one might want to overload new and delete operators for one’s own class. This present FAQ tries to explain how one does so in a standard-conforming way. Implementing a custom new operator The C++ standard (ยง18.4.1.1) defines operator new as: void* operator new (std::size_t size) throw (std::bad_alloc); … Read more
No, it is not safe to call delete on a stack-allocated variable. You should only call delete on things created by new. For each malloc or calloc, there should be exactly one free. For each new there should be exactly one delete. For each new[] there should be exactly one delete[]. For each stack allocation, … Read more
delete performs the check anyway, so checking it on your side adds overhead and looks uglier. A very good practice is setting the pointer to NULL after delete (helps avoiding double deletion and other similar memory corruption problems). I’d also love if delete by default was setting the parameter to NULL like in #define my_delete(x) … Read more
The C++ FAQ Lite has a entry specifically for this https://isocpp.org/wiki/faq/freestore-mgmt#delete-this I think this quote sums it up nicely As long as you’re careful, it’s OK for an object to commit suicide (delete this).
The delete operator deallocates memory and calls the destructor for a single object created with new. The delete [] operator deallocates memory and calls destructors for an array of objects created with new []. Using delete on a pointer returned by new [] or delete [] on a pointer returned by new results in undefined … Read more
Whether this leads to a memory leak, wipes your hard disk, gets you pregnant, makes nasty Nasal Demons chasing you around your apartment, or lets everything work fine with no apparent problems, is undefined. It might be this way with one compiler, and change with another, change with a new compiler version, with each new … Read more
Is being able to access data from beyond the grave expected? This is technically known as Undefined Behavior. Don’t be surprised if it offers you a can of beer either.
delete will delete the object property, but will not reindex the array or update its length. This makes it appears as if it is undefined: > myArray = [‘a’, ‘b’, ‘c’, ‘d’] [“a”, “b”, “c”, “d”] > delete myArray[0] true > myArray[0] undefined Note that it is not in fact set to the value undefined, … Read more