Re: memory leak in the code?

From:
=?UTF-8?B?RXJpayBXaWtzdHLDtm0=?= <Erik-wikstrom@telia.com>
Newsgroups:
comp.lang.c++
Date:
Sat, 05 Jan 2008 15:59:27 GMT
Message-ID:
<zPNfj.2462$R_4.1902@newsb.telia.net>
On 2008-01-05 16:04, George2 wrote:

Hello everyone,

Should I delete memory pointed by pointer a if there is bad_alloc when
allocating memory in memory pointed by pointer b? I am not sure
whether there will be memory leak if I do not delete a.

[Code]
try {
    a = new int [N];
    b = new int [M];
} catch (bad_alloc)
{
    // if a success, but b fail, should we try to delete[] a here to
avoid memory leak?

}
[/Code]


Yes, but what about if you get a bad_alloc when allocating a? Then you
will try to delete whatever memory that the garbage in a points to. To
prevent this use something like this instead:

try {
  int* a = 0;
  a = new int[N];
  int* b = new int[N];
}
catch (bad_alloc)
{
  delete[] a;
}

Or use some kind of smart pointer, in which case you do not need to try-
block since the pointers will free any memory if the exception is thrown.

  auto_ptr<int> a = new int[N];
  auto_ptr<int> b = new int[N];

Note also that depending on what type of application you are writing it
might be useless to catch bad_alloc (except for diagnostic purposes)
since it can be quite hard to recover from. In all applications I have
written a bad_alloc is a terminal failure.

--
Erik Wikstr?m

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