[Valgrind-users] [PATCH] possibly lost memory using new[] (not STL)

[Crispin F. <val...@fl...>]

Hi,

When using C++ and new[] with a class that has a destructor, it seems as
though the return address from the new[] is 4 bytes into the block
allocated. This causes the region of memory to be marked as 'possibly
lost'. It seems as though the 4 bytes is used to store the number of
items allocated, e.g. in the following program it will contain 1000.

#include <stdlib.h>
#include <stdio.h>

class inner {
public:
   inner() : ptr(0) {}
   ~inner() { if ( ptr ) delete ptr; }
   int * ptr;
};

inner * info;

int main( int argc, char ** argv )
{
   info = new inner[1000];
   exit(0);
}


This can be fixed by allowing pointers 4 bytes into a block created
using new[] and marking them as not lost.

The attached patch works for me [TM] (although I am not sure about the
assumption that the offset is always 4 bytes)

Cheers

Crispin