Looking for memory leaks freeware tools

Hello all
Is there good free ware tools to check software memory leaks ?
Some thing like purify

on unix platforms sun/hp/linux
Thanks

Here are a few C/C++ related memory leak tools to investigate:

mpatrol
njamd
fortify
electric fence
dmalloc

valgrind's Memcheck for linux

The dbx debugger provided with Sun Studio contains a memory access and leak checker. I've used it on Solaris for years.