Hello, all ... I searched in the old ActiveState message archive, but didn't find anything about this. When I compile my Boost experiments with gcc3.3, everything seems to be fine; when I compile them with gcc4, however, I get things like this (from the simple_ls example): pugsleybutt:~/devstuff/c++/boost jmzorko$ ./simple_ls usage: simple_ls [path] In directory: /Users/jmzorko/devstuff/c++/boost filesystem simple_ls(27587) malloc: *** Deallocation of a pointer not malloced: 0x2801b18; This could be a double free(), or free() called with the middle of an allocated block; Try setting environment variable MallocHelp to see tools to help debug filesystem.cpp simple_ls(27587) malloc: *** Deallocation of a pointer not malloced: 0x2801d00; This could be a double free(), or free() called with the middle of an allocated block; Try setting environment variable MallocHelp to see tools to help debug simple_ls simple_ls(27587) malloc: *** Deallocation of a pointer not malloced: 0x2801b00; This could be a double free(), or free() called with the middle of an allocated block; Try setting environment variable MallocHelp to see tools to help debug simple_ls.cpp simple_ls(27587) malloc: *** Deallocation of a pointer not malloced: 0x2801ce0; This could be a double free(), or free() called with the middle of an allocated block; Try setting environment variable MallocHelp to see tools to help debug 4 files 0 directories 0 errors pugsleybutt:~/devstuff/c++/boost jmzorko$ The Boost version is 1.31 and my platform is Mac OSX 10.4.6 (PowerPC), if that matters ... i'd like to use gcc4 if possible, can anyone tell me how to achieve this? Regards, John Falling You - exploring the beauty of voice and sound http://www.fallingyou.com