Re: bad_alloc

From:

"Ben Voigt [C++ MVP]" <rbv@nospam.nospam>

Newsgroups:

microsoft.public.vc.language

Date:

Wed, 26 Dec 2007 09:13:18 -0600

Message-ID:

<OJozfG9RIHA.4740@TK2MSFTNGP02.phx.gbl>

"George" <George@discussions.microsoft.com> wrote in message
news:8E64FB3F-021F-4A2D-9FF9-FCC0F9ACA875@microsoft.com...

Thanks Alex,

It is not correct to use delete or delete[] in bad_alloc handler code to
try
to free memory to reduce potential memory leak, right?

It is allowed, but not particularly likely to make retrying the allocation
succeed due to heap fragmentation. You'd better free any other resources
you obtained before the bad_alloc was thrown, though.

regards,
George

"Alex Blekhman" wrote:

"George" wrote:

Please help to comment whether my following understanding is
correct,

1. whether or not we are using auto_ptr to allocate new object
on heap
(using new), there may be bad_alloc exceptions;

Correct. The `std::bad_alloc' exception is thrown by `operator
new'. Whether `std::auto_ptr' is used or not is just not relevant.

2. when we met with such exceptions, we catch it (bad_alloc) and
try to
mininize the operation in catch handler block (since when
bad_alloc occurs,
it means memory is running out, we can not do anything complex
in handler).

Basically it's true. However, `std::bad_alloc' also can be thrown
if program tries to allocate continuous block of memory, which is
too large. In that case small allocations will succeed without a
problem.

Alex