Re: iword and sword problem
Erik wrote:
Bo Persson schrieb:
Erik wrote:
kanze schrieb:
Bo Persson wrote:
"Erik" <erik.griessmann@fmc-ag.com> skrev i meddelandet
news:1154496683.625736.118250@b28g2000cwb.googlegroups.com...
I used the static ios_base functions iword and sword in a
DLL-Library-Code to implement a manipulator. My Visual C++ 8
compiler
always complains about a memory leak, when the program is
terminated.
Is this a compiler specific problem?
Could be.
The leak detector is run at the end of main(), well before
global objects are destroyed.
That depends on the leak detector.
Yes, I'm referring to the leak detector built into the VC++ debug
mode. That one runs right after the main() function, but before
global objects are destructed. It simply reports what heap objects
are allocated at that point. Some of them might be released later.
Note, too, that cin, cout
and cerr are never destructed. If he has used his manipulator
on one of these, the memory it causes to be allocated will never
be freed. Some leak detectors might complain here, too,
regardless of how late they run. (It depends on the
sophistication of the leak detector; a good leak detector will
recognize that there are still pointers to the memory in static
objects, and only warn that there might be a leak.)
iword and pword are member functions of the class ios_base. Thus
the
problem shouldn't have smth. to do with cout, cin, cerr.
But those are of stream types that inherit from ios_base. Therefore
they might be affected.
I understand that the compiler complains about a memory leak. But
sword and iword allocate memory of a static array which is defined
in
ios_base. static data shouldn't not be destroyed when the destructur
of cout, cerr etc. is called. static data are destroyed when the
program calls the function atexit.
The array storing the values is not static, but allocated dynamically
for each stream needing one. From the library source (VC8) it looks
like the memory is deallocated in the destructor, if that is ever run.
Why the visual c++ compiler do not complain when I use a singleton
pattern with dynamic allocated memory. This memory will also be
released after the main-function.
I don't know. Perhaps the compiler handles that memory differently, so
that it is released earlier, or perhaps it is marked so that it is not
included in the leak detection. Memory blocks can be excluded, as an
allocation option.
Bo Persson
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