+ There are six flavors each of new and
+ delete, so make certain that you're using the right
+ ones. Here are quickie descriptions of new:
+
+ single object form, throwing a
+ bad_alloc on errors; this is what most
+ people are used to using
+
+ Single object "nothrow" form, returning NULL on errors +
+ Array new, throwing
+ bad_alloc on errors
+
+ Array nothrow new, returning
+ NULL on errors
+
+ Placement new, which does nothing (like
+ it's supposed to)
+
+ Placement array new, which also does
+ nothing
+
+ They are distinguished by the parameters that you pass to them, like
+ any other overloaded function. The six flavors of delete
+ are distinguished the same way, but none of them are allowed to throw
+ an exception under any circumstances anyhow. (They match up for
+ completeness' sake.)
+
+ Remember that it is perfectly okay to call delete on a
+ NULL pointer! Nothing happens, by definition. That is not the
+ same thing as deleting a pointer twice.
+
+ By default, if one of the âthrowing newsâ can't
+ allocate the memory requested, it tosses an instance of a
+ bad_alloc exception (or, technically, some class derived
+ from it). You can change this by writing your own function (called a
+ new-handler) and then registering it with set_new_handler():
+
+ typedef void (*PFV)(void);
+
+ static char* safety;
+ static PFV old_handler;
+
+ void my_new_handler ()
+ {
+ delete[] safety;
+ popup_window ("Dude, you are running low on heap memory. You
+ should, like, close some windows, or something.
+ The next time you run out, we're gonna burn!");
+ set_new_handler (old_handler);
+ return;
+ }
+
+ int main ()
+ {
+ safety = new char[500000];
+ old_handler = set_new_handler (&my_new_handler);
+ ...
+ }
+
+ bad_alloc is derived from the base exception
+ class defined in Chapter 19.
+