Nir Piterman wrote: > I have a strange problem with setting pointers to 0. It happens in a 64 > bit environment. > > I am using a big package (which I know very little about) and get it to > crash. > I can narrow the problem to some function that handles a pointer and on > returning from the function the pointer is changed (I completely don't > understand how is it possible that returning from a function can change > the pointer unless there is some memory leak). > > The thing is, when I print the pointer using printf instead of getting 8 > chars I get 12 chars. > The change that is done to the pointer is that the least 64 bits are set > to 0 and the top 32 bits remain unchanged (which could make some sense > if this memory was deallocated by some side effect that I don't see). > Furthermore, when I compare this pointer to 0 I get that it is not 0 > (and in my opinion this is what causes the program to crash). > > Does this ring a bell to anyone? Your'e almost certainly looking at memory corruption. Valgrind's memory checker would be a good start. Also, gdb supports watchpoints, so you can see when the pointer is changed. Andrew.
