dump valgrind data

Question

I am using valgrind on a program which runs an infinite loop.

As memcheck displays the memory leaks after the end of the program, but as my program has infinite loop it will never end.

So is there any way i can forcefully dump the data from valgrind time to time.

Thanks

Answer 1

Have a look at the client requests feature of memcheck. You can probably use VALGRIND_DO_LEAK_CHECK or similar.

EDIT:

In response to the statement above that this doesn't work. Here is an example program which loops forever:

#include <valgrind/memcheck.h>
#include <unistd.h>
#include <cstdlib>

int main(int argc, char* argv[])
{

  while(true) {
    char* leaked = new char[1];
    VALGRIND_DO_LEAK_CHECK;
    sleep(1);
  }

  return EXIT_SUCCESS;
}

When I run this in valgrind, I get an endless output of new leaks:

$ valgrind ./a.out
==16082== Memcheck, a memory error detector
==16082== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al.
==16082== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info
==16082== Command: ./a.out
==16082== 
==16082== LEAK SUMMARY:
==16082==    definitely lost: 0 bytes in 0 blocks
==16082==    indirectly lost: 0 bytes in 0 blocks
==16082==      possibly lost: 0 bytes in 0 blocks
==16082==    still reachable: 1 bytes in 1 blocks
==16082==         suppressed: 0 bytes in 0 blocks
==16082== Reachable blocks (those to which a pointer was found) are not shown.
==16082== To see them, rerun with: --leak-check=full --show-reachable=yes
==16082== 
==16082== 1 bytes in 1 blocks are definitely lost in loss record 2 of 2
==16082==    at 0x4C2BF77: operator new[](unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==16082==    by 0x4007EE: main (testme.cc:9)
==16082== 
==16082== LEAK SUMMARY:
==16082==    definitely lost: 1 bytes in 1 blocks
==16082==    indirectly lost: 0 bytes in 0 blocks
==16082==      possibly lost: 0 bytes in 0 blocks
==16082==    still reachable: 1 bytes in 1 blocks
==16082==         suppressed: 0 bytes in 0 blocks
==16082== Reachable blocks (those to which a pointer was found) are not shown.
==16082== To see them, rerun with: --leak-check=full --show-reachable=yes
==16082== 
==16082== 2 bytes in 2 blocks are definitely lost in loss record 2 of 2
==16082==    at 0x4C2BF77: operator new[](unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==16082==    by 0x4007EE: main (testme.cc:9)
==16082== 
==16082== LEAK SUMMARY:
==16082==    definitely lost: 2 bytes in 2 blocks
==16082==    indirectly lost: 0 bytes in 0 blocks
==16082==      possibly lost: 0 bytes in 0 blocks
==16082==    still reachable: 1 bytes in 1 blocks
==16082==         suppressed: 0 bytes in 0 blocks
==16082== Reachable blocks (those to which a pointer was found) are not shown.
==16082== To see them, rerun with: --leak-check=full --show-reachable=yes

The program does not terminate.

Answer 2

Use of VALGRIND_DO_LEAK_CHECK (acm answer) works for me.
Remarks :
- Program has to be launch with valgrind (valgrind myProg ...)
- valgrind-devel package has to be installed (to have )

Answer 3

with valgrind 3.7.0, you can trigger (a.o.) leak search from the shell, using vgdb.

See e.g. http://www.valgrind.org/docs/manual/mc-manual.html#mc-manual.monitor-commands (you can do these monitor commands from gdb or from a shell command line, using vgdb).