STL Memory Leak when compiling on11.00 HPUX using the aCC -AA flag

[Jeremy Lemaire]

Hello,

I am working on cross platform code that is displaying a huge memory
leak when compiled on 11.00 HPUX using the aCC -AA flag. It is not
leaking on NT, LINUX, Solaris, or HPUX without the -AA flag. In
another news group I came across some interesting (ok scarey)
information regarding memory leaks in the STL list<...> container. I
have compiled and executed the following code and verified that this
does in fact leak on my system.

#include "stdio.h"
#include "stdlib.h"
#include "malloc.h"

#include <list>
using namespace std;
template class list<int>;

int main (int argc, char *argv[])
{
list<int> list_int;
char c='r';

do
{
for ( int j = 0; j < 99999 ; j++ )
{
list_int.push_b ack(2);
list_int.pop_fr ont();
}

printf ( "\nPress r to repeat, q to exit\n=>" );
c = getchar ();
}
while ( c != 'q' );

return 0;
}

STL is used throughout my code. Has anyone run into this problem? If
so could you please let me know if you have come up with a fix, patch,
or work-around. Any help would be greatly appreciated.

Regards,
Jeremy

[Ivan Vecerina]

Re: STL Memory Leak when compiling on11.00 HPUX using the aCC -AA flag

"Jeremy Lemaire" <jlemaire@xl.co m> wrote in message
news:8a33fb62.0 310091322.41de1 af@posting.goog le.com...
....[color=blue]
> I am working on cross platform code that is displaying a huge
> memory leak when compiled on 11.00 HPUX using the aCC -AA flag.[/color]
Question: what does the -AA flag do, what do you need it for?
....[color=blue]
> I have compiled and executed the following code and verified
> that this does in fact leak on my system.[/color]
....[color=blue]
> for ( int j = 0; j < 99999 ; j++ )
> {
> list_int.push_b ack(2);
> list_int.pop_fr ont();
> }[/color]
....[color=blue]
> STL is used throughout my code. Has anyone run into this problem? If
> so could you please let me know if you have come up with a fix, patch,
> or work-around. Any help would be greatly appreciated.[/color]

What is the magnitude of the memory leak that you are observing?

The code you have posted should not leak any memory if
the std::list container is decently implemented.
If it does leak memory on your platform, can you step
through the code with a debugger and analyze where the
leak comes from ?

If it is a problem with the implementation of the standard
library that you are using, maybe using an alternative
implementation such as the free STLport (www.stlport.org)
will help.


Anyway, this is not a problem with standard C++ (as it is
specific to a platform and a given compiler setting).
You may want to request support in a forum dedicated
to the compiler you are using.

Regards,
Ivan
--

http://ivan.vecerina.com

[Jeremy Lemaire]

Re: STL Memory Leak when compiling on11.00 HPUX using the aCC -AA flag

"Ivan Vecerina" <ivecATmyrealbo xDOTcom> wrote in message news:<3f85d877@ news.swissonlin e.ch>...[color=blue]
> "Jeremy Lemaire" <jlemaire@xl.co m> wrote in message
> news:8a33fb62.0 310091322.41de1 af@posting.goog le.com...
> ...[color=green]
> > I am working on cross platform code that is displaying a huge
> > memory leak when compiled on 11.00 HPUX using the aCC -AA flag.[/color]
> Question: what does the -AA flag do, what do you need it for?[/color]

JL->Thanks for the quick response Ivan. This is from HP:

Description:
The new -AA command line option enables use of the new 2.0 Standard
C++ Library, which includes the new standard conforming
("templatize d") iostream library. This is the first release of the 2.0
library. It conforms to the ISO C++ standard.
[color=blue]
> ...[color=green]
> > I have compiled and executed the following code and verified
> > that this does in fact leak on my system.[/color]
> ...[color=green]
> > for ( int j = 0; j < 99999 ; j++ )
> > {
> > list_int.push_b ack(2);
> > list_int.pop_fr ont();
> > }[/color]
> ...[color=green]
> > STL is used throughout my code. Has anyone run into this problem? If
> > so could you please let me know if you have come up with a fix, patch,
> > or work-around. Any help would be greatly appreciated.[/color]
>
> What is the magnitude of the memory leak that you are observing?[/color]

JL->The software is used in a Call Processing environment and varies
according to call volume. The more messages processed with STL
containers the bigger the leak. In general 7-10 calls per second will
leak 2500 kbytes per hour at a constant rate until the process runs
out of memory and core dumps.
[color=blue]
>
> The code you have posted should not leak any memory if
> the std::list container is decently implemented.
> If it does leak memory on your platform, can you step
> through the code with a debugger and analyze where the
> leak comes from ?[/color]

JL->Here is the gdb output:

(gdb) where
#0 0x4b68 in std::list<int,s td::allocator<i nt>>::insert
(this=0x7f7f092 0,
#aggretxform#77 =@0x7f7f0950,
__it={<struct std::iterator<s td::bidirection al_iterator_tag ,int,long,int
*,int &>> = {<No data fields>}, _C_node = 0x40004cd8},
__x=@0x7f7f0940 )
at /opt/aCC/include_std/list:911
#1 0x4404 in main (argc=1, argv=0x7f7f076c ) at leakcode.cpp:18
(gdb) display this
2: this = (class std::list<int,s td::allocator<i nt> > *) 0x7f7f0920

But I am not sure how this will help. Should I attempt to modify the
std:list class?
[color=blue]
>
> If it is a problem with the implementation of the standard
> library that you are using, maybe using an alternative
> implementation such as the free STLport (www.stlport.org)
> will help.[/color]

JL->Good idea, the only problem is that I only have until the end of
today to resolve this. I was hoping for a quick fix like a patch or
adding a flag to the build line. I know, wishfull thinking.
[color=blue]
>
>
> Anyway, this is not a problem with standard C++ (as it is
> specific to a platform and a given compiler setting).
> You may want to request support in a forum dedicated
> to the compiler you are using.[/color]

JL->I tried one of the compiler forums and they refered me here.
Thanks again for the help.
[color=blue]
>
> Regards,
> Ivan[/color]

[Ivan Vecerina]

Re: STL Memory Leak when compiling on11.00 HPUX using the aCC -AA flag

Hi Jeremy,[color=blue]
> "Ivan Vecerina" <ivecATmyrealbo xDOTcom> wrote in message[/color]
news:<3f85d877@ news.swissonlin e.ch>...
.... (thanks for the info) ....[color=blue][color=green]
> > The code you have posted should not leak any memory if
> > the std::list container is decently implemented.
> > If it does leak memory on your platform, can you step
> > through the code with a debugger and analyze where the
> > leak comes from ?[/color][/color]
....[color=blue]
> But I am not sure how this will help. Should I attempt to modify the
> std:list class?[/color]
Well, it is only an option if you are sure that you understand its
implementation very well.
Its code would need to be carefully reviewed and understood...
[color=blue][color=green]
> > If it is a problem with the implementation of the standard
> > library that you are using, maybe using an alternative
> > implementation such as the free STLport (www.stlport.org)
> > will help.[/color]
>
> JL->Good idea, the only problem is that I only have until the end of
> today to resolve this. I was hoping for a quick fix like a patch or
> adding a flag to the build line. I know, wishfull thinking.[/color]

A possible workaround, if you are only using the std::list as
a queue, would be to replace this broken container with an
std::deque -- which also has the push_back/pop_front members.
[color=blue][color=green]
> > Anyway, this is not a problem with standard C++ (as it is
> > specific to a platform and a given compiler setting).
> > You may want to request support in a forum dedicated
> > to the compiler you are using.[/color]
>
> JL->I tried one of the compiler forums and they refered me here.[/color]

Well, all I can say is that the code sample you posted
should not leak any memory according to the C++ standard.
I would say that the standard library implementation
you use has a bug if this is steadily leaking memory.

[NB: btw, however, the following includes are incorrect
according to the C++ standard:
#include "stdio.h"
#include "stdlib.h"
#include "malloc.h"
This should be:
#include <cstdio>
#include <cstdlib>
// and malloc is defined in cstdlib already
]
[color=blue]
> Thanks again for the help.[/color]

Sorry I can't help further...

Sincerely,
Ivan
--

http://ivan.vecerina.com